Search for the Higgs Boson in theH→WW(*)→l+νl−ν¯Decay Channel inppCollisions ats=7  TeVwith the ATLAS Detector

A search for the Higgs boson has been performed in the H -> WW(*()) -> l+vl-(v) over bar channel (l = e/mu) with an integrated luminosity of 2.05 fb(-1) of pp collisions at root s = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. No significant excess of events over the expected background is observed and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range 110 GeV< m(H) < 300 GeV. The observations exclude the presence of a standard model Higgs boson with a mass 145 < m(H) < 206 GeV at 95% confidence level.

Amplitude analysis of the decayB±→π±π±π∓

We present a Dalitz-plot analysis of charmless B+- decays to the final state pi+- pi+- pi-+ using 210 fb^-1 of data recorded by the BABAR experiment at sqrt(s) = 10.58 GeV. We measure the branching fractions B(B+- -> pi+- pi+- pi-+) = (16.2 +- 1.2 +- 0.9) x 10^-6 and B(B+- -> rho^0(770) pi+-) = (8.8 +- 1.0 +- 0.6 +0.1-0.7) x 10^-6. Measurements of branching fractions for the quasi-two-body decays B+- -> rho^0(1450) pi+-, B+- -> f_0(980) pi+- and B+- -> f_2(1270) pi+- are also presented. We observe no charge asymmetries for the above modes, and there is no evidence for the decays B+- -> chic0 pi+-, B+- -> f_0(1370) pi+- and B+- -> sigma pi+-.

Search for new phenomena in the WW→lνl′ν′ final state in pp collisions at s=7TeV with the ATLAS detector

This Letter reports a search for a heavy particle that decays to WW using events produced in pp collisions at root s = 7 TeV. The data were recorded in 2011 by the ATLAS detector and correspond to an integrated luminosity of 4.7 fb(-1). WW -> lvl'v' (l,l' = e or mu) final states are considered and the distribution of the transverse mass of the W W candidates is found to be consistent with Standard Model expectations. Upper limits on the production cross section times branching ratio into W boson pairs are set for Randall-Sundrum and bulk Randall-Sundrum gravitons, which result in observed 95% CL lower limits on the masses of the two particles of 1.23 TeV and 0.84 TeV, respectively.

Search for contact interactions and large extra dimensions in dilepton events fromppcollisions ats=7  TeVwith the ATLAS detector

A search for nonresonant new phenomena, originating from either contact interactions or large extra spatial dimensions, has been carried out using events with two isolated electrons or muons. These events, produced at the LHC in proton-proton collisions at root s = 7 TeV, were recorded by the ATLAS detector. The data sample, collected throughout 2011, corresponds to an integrated luminosity of 4.9 and 5.0 fb(-1) in the e(+)e(-) and mu(+)mu(-) channels, respectively. No significant deviations from the Standard Model expectation are observed. Using a Bayesian approach, 95% confidence level lower limits ranging from 9.0 to 13.9 TeV are placed on the energy scale of llqq contact interactions in…

Measurement of theB0→K2*(1430)0γandB+→K2*(1430)+γbranching fractions

We have investigated the exclusive, radiative B meson decays to K2*(1430) in 89* 10^6 BBbar events with the BaBar detector at the PEP-II storage ring. We measure the branching fractions BR(B0 -> K2*(1430)0 gamma) = (1.22 +-0.25 +-0.10)*10^(-5) and BR(B+ -> K2*(1430)+ gamma) = (1.45 +-0.40 +-0.15) * 10^(-5), where the first error is statistical and the second systematic. In addition, we measure the CP-violating asymmetry ACP(B0 -> K2*(1430)0 gamma) = -0.08 +- 0.15 +- 0.01.

Performance of jet substructure techniques for large-$R$ jets in proton-proton collisions at $\sqrt{s}$ = 7 TeV using the ATLAS detector

This paper presents the application of a variety of techniques to study jet substructure. The performance of various modified jet algorithms, or jet grooming techniques, for several jet types and event topologies is investigated for jets with transverse momentum larger than 300 GeV. Properties of jets subjected to the mass-drop filtering, trimming, and pruning algorithms are found to have a reduced sensitivity to multiple proton-proton interactions, are more stable at high luminosity and improve the physics potential of searches for heavy boosted objects. Studies of the expected discrimination power of jet mass and jet substructure observables in searches for new physics are also presented.…

Search for the highly suppressed decaysB−→K+π−π−andB−→K−K−π+

We report a search for the decays B- -> K+pi(-)pi(-) and B- -> K-K-pi(+), which are highly suppressed in the standard model. Using a sample of (467 +/- 5) x 10(6) B (B) over bar pairs collected with the BABAR detector, we do not see any evidence of these decays and determine 90% confidence level upper limits of B(B- -> K+pi(-)pi(-)) and K-K-pi(+)) and < 1.6 x 10(-7) on the corresponding branching fractions, including systematic uncertainties.

Measurement of the semileptonic decaysB¯→Dτ−ν¯τandB¯→D*τ−ν¯τ

We present measurements of the semileptonic decays B{sup -}{yields}D{sup 0}{tau}{sup -}{nu}{sub {tau}}, B{sup -}{yields}D*{sup 0}{tau}{sup -}{nu}{sub {tau}}, B{sup 0}{yields}D{sup +}{tau}{sup -}{nu}{sub {tau}}, and B{sup 0}{yields}D*{sup +}{tau}{sup -}{nu}{sub {tau}}, which are sensitive to non-standard model amplitudes in certain scenarios. The data sample consists of 232x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider. We select events with a D or D* meson and a light lepton (l=e or {mu}) recoiling against a fully reconstructed B meson. We perform a fit to the joint distribution of lepton momentum and missing mass squared …

Search forCPTand Lorentz Violation inB0−B¯0Oscillations with Dilepton Events

We report results of a search for CPT and Lorentz violation in B{sup 0}-{bar B}{sup 0} oscillations using inclusive dilepton events from 232 million {Upsilon}(4S) {yields} B{bar B} decays recorded by the BABAR detector at the PEP-II B Factory at SLAC. We find 2.8{sigma} significance, compatible with no signal, for variations in the complex CPT violation parameter z at the Earth's sidereal frequency and extract values for the quantities {Delta}a{sub {mu}} in the general Lorentz-violating standard-model extension. The spectral powers for variations in z over the frequency range 0.26 year{sup -1} to 2.1 day{sup -1} are also compatible with no signal.

Precise branching ratio measurements of the decaysD0→π−π+π0andD0→K−K+π0relative to theD0→K−π+π0decay

Using 232 fb-1 of e+e- collision data recorded by the BaBar experiment, we measure the ratios of three-body Cabibbo-suppressed decay rates of the D^0 meson relative to that of the Cabibbo-favored decay: B(D0 --> pi- pi+ pi0)/ B(D0 --> K- pi+ pi0) = (10.59 +/- 0.06 +/- 0.13).10^{-2} and B(D0 --> K- K+ pi0)/ B(D0 --> K- pi+ pi0) = (2.37 +/- 0.03 +/- 0.04). 10^{-2}, where the errors are statistical and systematic respectively. The precisions of these measurements are significantly better than those of the current world average values.We note that the second result differs significantly from the current world average value. Using the PDG-2006 value for D0 --> K- pi+ pi0 branching fraction, we o…

Observation of an Excited Charm BaryonΩc*Decaying toΩc0γ

We report the first observation of an excited singly-charm baryon OmegaC* (css) in the radiative decay OmegaC0 Gamma, where the OmegaC0 baryon is reconstructed in the decays to the final states Omega-pi+, Omega-pi+pi0, Omega-pi+pi-pi+, and Cascade-K-pi+pi+. This analysis is performed using a dataset of 230.7 fb$-1} collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. The mass difference between the OmegaC* and the OmegaC0 baryons is measured to be 70.8 +/- 1.0 (stat) +/- 1.1 (syst) MeV/c2. We also measure the ratio of inclusive production cross sections of OmegaC* and OmegaC0 in e+e- annihilation.

Measurement of branching fractions in radiativeBdecays toηKγand search forBdecays toη′Kγ

We present measurements of the B ->eta K gamma branching fractions and upper limits for the B ->eta K-'gamma branching fractions. For B+->eta K+gamma we also measure the time-integrated charge asymmetry. The data sample, collected with the BABAR detector at the Stanford Linear Accelerator Center, represents 232x10(6) produced B (B) over bar pairs. The results for branching fractions and upper limits at 90% confidence level in units of 10(-6) are: B(B-0 ->eta K-0 gamma)=11.3(-2.6)(+2.8)+/- 0.6, B(B+->eta K+gamma)=10.0 +/- 1.3 +/- 0.5, B(B-0 ->eta K-'(0)gamma) eta K-'(+)gamma) eta K+gamma is A(ch)=-0.09 +/- 0.12 +/- 0.01. The first errors are statistical and the second systematic.

Measurement of the charge asymmetry in top quark pair production in pp collisions at root s=7 TeV using the ATLAS detector

A measurement of the top-antitop production charge asymmetry A[subscript C] is presented using data corresponding to an integrated luminosity of 1.04 fb[superscript −1] of pp collisions at s√=7 TeV collected by the ATLAS detector at the LHC. Events are selected with a single lepton (electron or muon), missing transverse momentum and at least four jets of which at least one jet is identified as coming from a b-quark. A kinematic fit is used to reconstruct the t[bar over t] event topology. After background subtraction, a Bayesian unfolding procedure is performed to correct for acceptance and detector effects. The measured value of A[subscript C] is A[subscript C]=−0.019±0.028 (stat.)±0.024 (s…

Evidence forB+→K¯0K+andB0→K0K¯0, and Measurement of the Branching Fraction and Search for DirectCPViolation inB+→K0π+

The authors present evidence for the b {yields} d penguin-dominated decays B{sup +} {yields} {bar K}{sup 0}K{sup +} and B{sup 0} {yields} K{sup 0}{bar K}{sup 0} with significances of 3.5 and 4.5 standard deviations, respectively. The results are based on a sample of 227 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. We measure the branching fractions {Beta}(B{sup +} {yields} {bar K}{sup 0}K{sup +}) = (1.5 {+-} 0.5 {+-} 0.1) x 10{sup -6} (< 2.4 x 10{sup -6}) and {Beta}(B{sup 0} {yields} K{sup 0}{bar K}{sup 0}) = (1.19{sub -0.35}{sup +0.40} {+-} 0.13) x 10{sup -6}, where the uncertainties are …

Search for New Phenomena intt¯Events with Large Missing Transverse Momentum in Proton-Proton Collisions ats=7  TeVwith the ATLAS Detector

A search for new phenomena in tt events with large missing transverse momentum in proton-proton collisions at a center-of-mass energy of 7 TeV is presented. The measurement is based on 1.04  fb-1 of data collected with the ATLAS detector at the LHC. Contributions to this final state may arise from a number of standard model extensions. The results are interpreted in terms of a model where new top-quark partners are pair produced and each decay to an on-shell top (or antitop) quark and a long-lived undetected neutral particle. The data are found to be consistent with standard model expectations. A limit at 95% confidence level is set excluding a cross section times branching ratio of 1.1 pb …

Measurement of the flavour composition of dijet events in pp collisions at √s = 7 TeV with the ATLAS detector

This paper describes a measurement of the flavour composition of dijet events produced in pp collisions at s√=7~TeVs=7~TeV using the ATLAS detector. The measurement uses the full 2010 data sample, corresponding to an integrated luminosity of 39 pb−1. Six possible combinations of light, charm and bottom jets are identified in the dijet events, where the jet flavour is defined by the presence of bottom, charm or solely light flavour hadrons in the jet. Kinematic variables, based on the properties of displaced decay vertices and optimised for jet flavour identification, are used in a multidimensional template fit to measure the fractions of these dijet flavour states as functions of the leadin…

Measurements of the decaysB0→D¯0pp¯,B0→D¯*0pp¯,B0→D−pp¯π+, andB0→D*−pp¯π+

We present measurements of branching fractions of $B^0$ decays to multi-body final states containing protons, based on 232 million $\Upsilon(4S)\to B\bar{B}$ decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy $B$ factory. We measure the branching fractions ${\cal B}(B^0 \to \bar{D}^0\proton\antiproton)=(1.13\pm0.06\pm0.08)\times 10^{-4}$, ${\cal B}(B^0 \to \bar{D}^{*0}\proton\antiproton)=(1.01\pm0.10\pm0.09)\times 10^{-4}$, ${\cal B}(B^0 \to D^{-}\proton\antiproton\pi^+)=(3.38\pm0.14\pm0.29)\times 10^{-4}$, and ${\cal B}(B^0 \to D^{*-}\proton\antiproton\pi^+)=(4.81\pm0.22\pm0.44)\times 10^{-4}$ where the first error is statistical and the second systematic. We pre…

Measurement of the azimuthal anisotropy for charged particle production insNN=2.76TeV lead-lead collisions with the ATLAS detector

Differential measurements of charged particle azimuthal anisotropy are presented for lead-lead collisions at root sNN = 2.76 TeV with the ATLAS detector at the LHC, based on an integrated luminosity of approximately 8 mu b(-1). This anisotropy is characterized via a Fourier expansion of the distribution of charged particles in azimuthal angle relative to the reaction plane, with the coefficients v(n) denoting the magnitude of the anisotropy. Significant v(2)-v(6) values are obtained as a function of transverse momentum (0.5 = 3 are found to vary weakly with both eta and centrality, and their p(T) dependencies are found to follow an approximate scaling relation, v(n)(1/n)(p(T)) proportional …

Measurement of the top quark pair production cross-section with ATLAS in the single lepton channel

A measurement of the production cross-section for top quark pairs (t[bar over t]) in pp collisions at √s = 7 TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in the single lepton topology by requiring an electron or muon, large missing transverse momentum and at least three jets. With a data sample of 35 pb[superscript −1], two different multivariate methods, one of which uses b-quark jet identification while the other does not, use kinematic variables to obtain cross-section measurements of σ[subscript t bar over t] = 187 ± 11 (stat.) [+18 over −17] (syst.) ± 6 (lumi.) pb and σ[subscript t bar over t] = 173 ± 17 (stat.) [+18 ove…

Search for the decayB+→K¯*0(892)K+

We report on a search for the process B+ -> (K) over bar*(0)(892)K+ using 232 X 10(6) Y(4S) -> B (B) over bar B decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. From a signal yield of 25 +/- 13[stat] +/- 7[syst] B+ -> (K) over bar*(0)(892)(-> K-pi(+))K+ events, we place an upper limit on the branching fraction B(B+ -> (K) over bar*(0)(892)K+) of 1.1 X 10(-6), at the 90% confidence level.

A search for flavour changing neutral currents in top-quark decays in pp collision data collected with the ATLAS detector at root s=7 TeV

A search for flavour changing neutral current (FCNC) processes in top-quark decays by the ATLAS Collaboration is presented. Data collected from pp collisions at the LHC at a centre-of-mass energy of √s = 7 TeV during 2011, corresponding to an integrated luminosity of 2.1 fb[superscript −1], were used. A search was performed for top-quark pair-production events, with one top quark decaying through the t → Zq FCNC (q = u, c) channel, and the other through the Standard Model dominant mode t → W b. Only the decays of the Z boson to charged leptons and leptonic W -boson decays were considered as signal. Consequently, the final-state topology is characterised by the presence of three isolated cha…

Measurement ofCP-violating asymmetries inB0→(ρπ)0decays using a time-dependent Dalitz plot analysis

We report on a measurement of CP-violating asymmetries (A{sub CP}) in the Cabibbo-suppressed D{sup 0} {yields} {pi}{sup +}{pi}{sup -} and D{sup 0} {yields} K{sup +}K{sup -} decays reconstructed in a data sample corresponding to 5.9 fb{sup -1} of integrated luminosity collected by the upgraded Collider Detector at Fermilab. We use the strong decay D*{sup +} {yields} D{sup 0}{pi}{sup +} to identify the flavor of the charmed meson at production and exploit CP-conserving strong c{bar c} pair-production in p{bar p} collisions. High-statistics samples of Cabibbo-favored D{sup 0} {yields} K{sup -}{pi}{sup +} decays with and without a D*{sup {+-}} tag are used to correct for instrumental effects an…

Branching fraction limits forB0decays toη′η,η′π0andηπ0

We describe searches for decays to two-body charmless final states eta(')eta, eta(')pi(0) and eta pi(0) of B-0 mesons produced in e(+)e(-) annihilation. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 232x10(6) produced B (B) over bar pairs. The results for branching fractions are, in units of 10(-6) (upper limits at 90% C.L.): B(B-0->eta(')eta)=0.2(-0.5)(+0.7)+/- 0.4( eta pi(0))=0.6(-0.4)(+0.5)+/- 0.1( eta(')pi(0))=0.8(-0.6)(+0.8)+/- 0.1(< 2.1). The first error quoted is statistical and the second systematic.

Branching fraction measurement ofB¯0→D(*)+π−andB−→D(*)0π−and isospin analysis ofB¯→D(*)πdecays

Using 65 X 10(6) Y (4S) -> BB events collected with the BABAR detector at the PEP-II e(+) e(-) storage ring at the Stanford Linear Accelerator Center, we measure the color-favored branching fractions B(B-0 -> D+ pi(-)) = (2.55 +/- 0.05 +/- 0.16) X 10(-3), B(B-0 -> D*(+) pi(-)) = (2.79 +/- 0.08 +/- 0.17) X 10(-3), B(B- -> D-0 pi(-)) = (4.90 +/- 0.07 +/- 0.22) X 10(-3) and B(B- -> D*(0)pi(-)) = (5.52 +/- 0.17 +/- 0.42) X 10(-3), where the first error is statistical and the second is systematic. With these results and the current world average for the branching fraction for the color-suppressed decay B-0 -> D-(*()0)pi(0), the cosines of the strong phase difference delta between the I =1/2 and …

Measurements of theB→Xsγbranching fraction and photon spectrum from a sum of exclusive final states

Using 88.9 million BB events collected by the BaBar detector at the Y(4S), we measure the branching fraction for the radiative penguin process B -> X_s gamma from the sum of 38 exclusive final states. The inclusive branching fraction above a minimum photon energy E_gamma > 1.9 GeV is BF (b -> s gamma) = (3.27 +/- 0.18 (stat.) +0.55/-0.40 (syst.) +0.04/-0.09 (theory)) 10^-4. We also measure the isospin asymmetry between B^- -> X_s ubar gamma and B^0bar -> X_s dbar gamma to be Delta_0- = -0.006 +/- 0.058 (stat.) +/- 0.009 (syst.) +/- 0.024 (B^0bar / B^-). The photon energy spectrum is measured in the B rest frame, from which moments are derived for different values of the minimum photon energ…

Evidence for directCPviolation from Dalitz-plot analysis ofB±→K±π∓π±

We report a Dalitz-plot analysis of the charmless hadronic decays of charged B mesons to the final state K+/- pi+/- pi-/+. Using a sample of 383.2 +/- 4.2 million BBbar pairs collected by the BaBar detector, we measure CP-averaged branching fractions and direct CP asymmetries for intermediate resonant and nonresonant contributions. We find evidence for direct CP violation in the decay B+ -> rho0(770) K+, with a CP violation parameter A_CP = (+44 +/- 10 +/- 4 +5,-13)%.

Study of the decayDs+→K+K−e+νe

Using 214fb-1 of data recorded by the BABAR detector at the PEPII electron-positron collider, we study the decay Ds+→K+K-e+νe. Except for a small S-wave contribution, the events with K+K- masses in the range 1.01-1.03GeV/c2 correspond to mesons. For Ds+→ e+νe decays, we measure the relative normalization of the Lorentz invariant form factors at q2=0, rV=V(0)/A1(0)=1.849±0.060±0.095, r2=A2(0)/A1(0)=0.763±0. 071±0.065 and the pole mass of the axial-vector form factors mA=(2.28-0.18+0.23±0.18)GeV/c2. Within the same K+K- mass range, we also measure the relative branching fraction B(Ds+→K+K-e+νe)/B(Ds+→K+K- π+)=0.558±0.007±0.016, from which we obtain the total branching fraction B(Ds+→ e+νe)=(2…

Measurement of charged-particle event shape variables in inclusive(s)=7  TeVproton-proton interactions with the ATLAS detector

The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor, and transverse sphericity, each defined using the final-state charged particles' momentum components perpendicular to the beam direction. Events with at least six charged particles are selected by a minimum-bias trigger. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged-particle transverse momentum, charged-particle multiplicity, and summed transverse momentum is presented.…

Search for a fermiophobic Higgs boson in the diphoton decay channel with the ATLAS detector

[Excerpt] A search for a fermiophobic Higgs boson using diphoton events produced in proton-proton collisions at a centre-of-mass energy of s√=7 TeV is performed using data corresponding to an integrated luminosity of 4.9 fb−1 collected by the ATLAS experiment at the Large Hadron Collider. A specific benchmark model is considered where all the fermion couplings to the Higgs boson are set to zero and the bosonic couplings are kept at the Standard Model values (fermiophobic Higgs model). The largest excess with respect to the background-only hypothesis is found at 125.5 GeV, with a local significance of 2.9 standard deviations, which reduces to 1.6 standard deviations when taking into account …

Measurement of the Mass Difference m(B0) - m(B+)

Using 230 million B Bbar events recorded with the BABAR detector at the e+ e- storage rings PEP-II, we reconstruct approximately 4100 B0 to J/psi K+ pi- and 9930 B+ to J/psi K+ decays with J/psi to mu+ mu- and e+ e-. From the measured B-momentum distributions in the e+ e- rest frame, we determine the mass difference m(B0) - m(B+) = (+0.33 +- 0.05 +- 0.03) MeV/c^2.

Measurement of branching fractions ofBdecays toK1(1270)πandK1(1400)πand determination of the CKM angleαfromB0→a1(1260)±π∓

We report measurements of the branching fractions of neutral and charged B meson decays to final states containing a K_1(1270) or K_1(1400) meson and a charged pion. The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, correspond to 454×10^6 BB pairs produced in e^+e^- annihilation. We measure the branching fractions B(B^0→K_1(1270)^+π-+K_1(1400)^+π-)=3.1_(-0.7)^(+0.8)×10^(-5) and B(B^+→K_1(1270)^0π^++K_1(1400)^0π^+)=2.9_(-1.7)^(+2.9)×10^(-5) (<8.2×10^(-5) at 90% confidence level), where the errors are statistical and systematic combined. The B^0 decay mode is observed with a significance of 7.5σ, while a significance of 3.2σ is obtained for the B^+ decay…

Measurement of theW+W−Cross Section ins=7  TeVppCollisions with ATLAS

This Letter presents a measurement of the W+W- production cross section in root s = 7 TeV pp collisions by the ATLAS experiment, using 34 pb(-1) of integrated luminosity produced by the Large Hadron Collider at CERN. Selecting events with two isolated leptons, each either an electron or a muon, 8 candidate events are observed with an expected background of 1.7 +/- 0.6 events. The measured cross section is 41(-16)(+20)(stat) +/- 5(syst) +/- 1(lumi) pb, which is consistent with the standard model prediction of 44 +/- 3 pb calculated at next-to-leading order in QCD.

Measurement of the hadronic form factor inD0→K−e+νedecays

We present a preliminary measurement of the q2 dependence of the D0 --> K- e+ nu_e decay rate. This rate is proportional to the hadronic form factor squared, specified by a single parameter. This is either the mass in the simple pole ansatz m_pole = (1.854 +- 0.016 +- 0.020) GeV/c2 or the scale in the modified pole ansatz alpha_pole = 0.43 +- 0.03 +- 0.04. The first error refers to the statistical, the second to the systematic uncertainty.

Study of jets produced in association with aWboson inppcollisions ats=7  TeVwith the ATLAS detector

We report a study of final states containing a W boson and hadronic jets, produced in proton-proton collisions at a center-of-mass energy of 7 TeV. The data were collected with the ATLAS detector at the CERN LHC and comprise the full 2010 data sample of 36 pb^-1. Cross sections are determined using both the electron and muon decay modes of the W boson and are presented as a function of inclusive jet multiplicity, N_jet, for up to five jets. At each multiplicity, cross sections are presented as a function of jet transverse momentum, the scalar sum of the transverse momenta of the charged lepton, missing transverse momentum, and all jets, the invariant mass spectra of jets, and the rapidity d…

Search for the radiative decay B0→γ

We perform a search for the exclusive radiative decay B0→γ, which is dominated by b̄d annihilation, in a sample of 124×106 BB̄ events collected with the BABAR detector at the PEP-II asymmetric-energy e+e- storage ring at SLAC. No significant signal is seen. We set an upper limit on the branching fraction of B(B0→γ)&lt;8. 5×10-7 at the 90% confidence level. © 2005 The American Physical Society.

Study of theτ−→3h−2h+ντdecay

The branching fraction of the tau- --> 3h- 2h+ nu decay (h= pi, kaon) is measured with the BaBar detector to be (8.56 +/- 0.05 +/- 0.42)E-04 where the first error is statistical and the second systematic. The observed structure of this decay is significantly different from the phase space prediction, with the rho resonance playing a strong role. The decay tau- --> f1 pi nu with the f1 meson decaying to four charged pions, is observed and the branching fraction is measured to be (3.9 +/- 0.7 +/- 0.5)E-04.

B-meson decays toη′ρ,η′f0, andη′K*

We present measurements of B-meson decays to the final states η′ρ, η′f_0, and η′K*, where K* stands for a vector, scalar, or tensor strange meson. We observe a significant signal or evidence for η′ρ^+ and all the η′K* channels. We also measure, where applicable, the charge asymmetries, finding results consistent with no direct CP violation in all cases. The measurements are performed on a data sample consisting of 467 × 10^6 BB(overbar) pairs, collected with the BABAR detector at the PEP-II e^+e^- collider at the SLAC National Accelerator Laboratory. Our results favor the theoretical predictions from perturbative QCD and QCD factorization and we observe an enhancement of the tensor K*_2(143…

Search forb→utransitions inB±→[K∓π±π0]DK±decays

We report results from an updated study of the suppressed decays ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}D{K}^{\ensuremath{-}}$ and ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{*}{K}^{\ensuremath{-}}$ followed by $D\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$, where ${D}^{(*)}$ indicates a ${D}^{(*)0}$ or a ${\overline{D}}^{(*)0}$ meson, and ${D}^{*}\ensuremath{\rightarrow}D{\ensuremath{\pi}}^{0}$ or ${D}^{*}\ensuremath{\rightarrow}D\ensuremath{\gamma}$. These decays are sensitive to the Cabibbo-Kobayashi-Maskawa unitarity triangle angle $\ensuremath{\gamma}$ due to interference between the $b\ensuremath{\rightarrow}c$ transition ${B}^{\ensuremath{-}}\ensure…

The ATLAS Simulation Infrastructure

52 páginas, 10 figuras, 18 tablas.-- This article is distributed under the terms of the Creative Commons Attribution Noncommercial License.-- et al. (The ATLAS Collaboration).

Jet mass and substructure of inclusive jets in $ \sqrt {s} = 7\;{\text{TeV}} $ pp collisions with the ATLAS experiment

Recent studies have highlighted the potential of jet substructure techniques to identify the hadronic decays of boosted heavy particles. These studies all rely upon the assumption that the internal substructure of jets generated by QCD radiation is well understood. In this article, this assumption is tested on an inclusive sample of jets recorded with the ATLAS detector in 2010, which corresponds to 35 pb-1 of pp collisions delivered by the LHC at √s = 7TeV. In a subsample of events with single pp collisions, measurements corrected for detector efficiency and resolution are presented with full systematic uncertainties. Jet invariant mass, kt splitting scales and N-subjettiness variables are…

Search for Strange-Pentaquark Production ine+e−Annihilation ats=10.58  GeV

We search for strange-pentaquark states that have been previously reported by other experiments--the Theta (1540)(+), Xi(5)(1860)(--), and Xi(5)(1860)(0)--in 123 fb(-1) of data recorded with the BABAR detector at the PEP-II e(+)e(-) storage ring. We find no evidence for these states and set 95% confidence level upper limits on the number of Theta(1540)(+) and Xi(5)(1860)(--) pentaquarks produced per e(+)e(-) annihilation into qq and Gamma(4S) decay. For qq events the Theta(1540)(+) [Xi(5)(1860)(--)] limit is about 8 [4] times lower than the rates measured for ordinary baryons of similar mass.

Measurement ofcos2βinB0→D(*)h0Decays with a Time-Dependent Dalitz Plot Analysis ofD→Ks0π+π−

We study the time-dependent Dalitz plot of D-->K_{S};{0}pi;{+}pi;{-} in B;{0}-->D;{(*)}h;{0} decays, where h;{0} is a pi;{0}, eta, eta;{'}, or omega meson and D;{*}-->Dpi;{0}, using a data sample of 383x10;{6} Upsilon(4S)-->BB[over ] decays collected with the BABAR detector. We determine cos2beta=0.42+/-0.49+/-0.09+/-0.13, sin2beta=0.29+/-0.34+/-0.03+/-0.05, and |lambda|=1.01+/-0.08+/-0.02, where the first error is statistical, the second is the experimental systematic uncertainty, and the third, where given, is the Dalitz model uncertainty. Assuming the world average value for sin2beta and |lambda|=1, cos2beta>0 is preferred over cos2beta<0 at 86% confidence level.

Measurements of the pseudorapidity dependence of the total transverse energy in proton-proton collisions at sqrt(s) = 7 TeV with ATLAS

This paper describes measurements of the sum of the transverse energy of particles as a function of particle pseudorapidity, η, in proton-proton collisions at a centre-of-mass energy, √s = 7 TeV using the ATLAS detector at the Large Hadron Collider. The measurements are performed in the region |η| < 4.8 for two event classes: those requiring the presence of particles with a low transverse momentum and those requiring particles with a significant transverse momentum. In the second dataset measurements are made in the region transverse to the hard scatter. The distributions are compared to the predictions of various Monte Carlo event generators, which generally tend to underestimate the amoun…

Limit on theB0→ρ0ρ0Branching Fraction and Implications for the Cabibbo-Kobayashi-Maskawa Angleα

The authors search for the decay B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0} in a data sample of about 227 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. They find no significant signal and set an upper limit of 1.1 x 10{sup -6} at 90% CL on the branching fraction. As a result, the uncertainty due to penguin contributions on the CKM unitarity angle {alpha} measured in B {yields} {rho}{rho} decays is 11{sup o} at 68% CL.

Measurement of the transverse momentum distribution ofWbosons inppcollisions ats=7  TeVwith the ATLAS detector

This paper describes a measurement of the W boson transverse momentum distribution using ATLAS pp collision data from the 2010 run of the LHC at root s = 7 TeV, corresponding to an integrated lumin ...

Observation of DecaysB0→Ds(*)+π−andB0→Ds(*)−K+

We report the observation of decays B-0 -> D-s((*)+)pi(-) and B-0 -> Ds(*)-K+ in a sample of 230x10(6) Upsilon(4S)-> BB events recorded with the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)e(-) storage ring. We measure the branching fractions B(B-0 -> D-s(+)pi(-))=(1.3 +/- 0.3(stat)+/- 0.2(syst))x10(-5), B(B-0 -> Ds-K+)=(2.5 +/- 0.4(stat)+/- 0.4(syst))x10(-5), B(B-0 -> D-s(*+)pi(-))=(2.8 +/- 0.6(stat)+/- 0.5(syst))x10(-5), and B(B-0 -> Ds*-K+)=(2.0 +/- 0.5(stat)+/- 0.4(syst))x10(-5). The significances of the measurements to differ from zero are 5, 9, 6, and 5 standard deviations, respectively. This is the first observation of B-0 -> D-s(+)pi(-), B-0 -> D-s(*+)pi(-), and B-0 -> D…

Production and decay of Ωc0

We present an analysis of inclusive Omega(c)(0) baryon production and decays in 230.5 fb(-1) of data recorded with the BABAR detector. Omega(c)(0) baryons are reconstructed in four final states (Omega(-)pi(+), Omega(-)pi(+)pi(0), Omega(-)pi(+)pi(+)pi(-), Xi(-)K(-)pi(+)pi(+)) and the corresponding ratios of branching fractions are measured. We also measure the momentum spectrum in the e(+)e(-) center-of-mass frame. From the spectrum, we observe Omega(c)(0) production from B decays and in cc events, and extract the two rates of production.

Measurement of the branching fraction and theCP-violating asymmetry for the decayB0→KS0π0

The authors measure the branching fraction and the CP-violating asymmetry of B{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0} decays with 227 million {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. They obtain a branching fraction {Beta}(B{sup 0} {yields} K{sup 0}{pi}{sup 0}) = (11.4 {+-} 0.9 {+-} 0.6) x 10{sup -6} and CP-violating asymmetry parameters C{sub K{sub S}{sup 0}{pi}{sup 0}} = 0.06 {+-} 0.18 {+-} 0.03 and S{sub K{sub S}{sup 0}{pi}{sup 0}} = 0.35{sub -0.33}{sup +0.30} {+-} 0.04, where the first error is statistical and the second systematic.

Search for supersymmetry in final states with jets, missing transverse momentum and one isolated lepton ins=7  TeVpp collisions using1  fb−1of ATLAS data

We present an update of a search for supersymmetry in final states containing jets, missing transverse momentum, and one isolated electron or muon, using 1.04 fb(-1) of proton-proton collision data at root s =7 TeV recorded by the ATLAS experiment at the LHC in the first half of 2011. The analysis is carried out in four distinct signal regions with either three or four jets and variations on the (missing) transverse momentum cuts, resulting in optimized limits for various supersymmetry models. No excess above the standard model background expectation is observed. Limits are set on the visible cross section of new physics within the kinematic requirements of the search. The results are inter…

Search for a Standard Model Higgs Boson in theH→ZZ→ℓ+ℓ−νν¯Decay Channel with the ATLAS Detector

A search for a heavy standard model Higgs boson decaying via H -> ZZ -> l(+)l(-)v (v) over bar, where l = e, mu, is presented. It is based on proton-proton collision data at root s = 7 TeV, collected by the ATLAS experiment at the LHC in the first half of 2011 and corresponding to an integrated luminosity of 1.04 fb(-1). The data are compared to the expected standard model backgrounds. The data and the background expectations are found to be in agreement and upper limits are placed on the Higgs boson production cross section over the entire mass window considered; in particular, the production of a standard model Higgs boson is excluded in the region 340 < m(H) < 450 GeV at the 95% confiden…

A study of the material in the ATLAS inner detector using secondary hadronic interactions

The ATLAS inner detector is used to reconstruct secondary vertices due to hadronic interactions of primary collision products, so probing the location and amount of material in the inner region of ATLAS. Data collected in 7 TeV pp collisions at the LHC, with a minimum bias trigger, are used for comparisons with simulated events. The reconstructed secondary vertices have spatial resolutions ranging from ~ 200μm to 1 mm. The overall material description in the simulation is validated to within an experimental uncertainty of about 7%. This will lead to a better understanding of the reconstruction of various objects such as tracks, leptons, jets, and missing transverse momentum.

Search ForT,CP, andCPTViolation inB0−B¯0Mixing with Inclusive Dilepton Events

The authors report the results of a search for T, CP and CPT violation in B{sup 0}-{bar B}{sup 0} mixing using an inclusive dilepton sample collected by the BABAR experiment at the PEP-II B Factory. Using a sample of 232 million B{bar B} pairs, with a simultaneous likelihood fit of the same-sign and opposite-sign dileptons, they measure the T and Cp violation parameter |q/p|-1 = (-0.8 {+-} 2.7(stat.) {+-} 1.9(syst.)) x 10{sup -3}, and the CPT and CP parameters Im z = (-13.9 {+-} 7.3(stat.) {+-} 3.2(syst.)) x 10{sup -3} and {Delta}{Lambda} x Re z = (-7.1 {+-} 3.9(stat.) {+-} 2.0(syst.)) x 10{sup -3} ps{sup -1}. The statistical correlation between the measurements of Im z and {Delta}{Lambda} …

Observation ofCPViolation inB→η′K0Decays

We report observations of CP violation in the decays B0 -> K+pi- and B0 -> pi+pi- in a sample of 383 million Y4S -> BBbar events. We find 4372 +/- 82 B0 -> K+pi- decays and measure the direct CP-violating charge asymmetry Akpi = -0.107 +/- 0.018 (stat) +0.007-0.004 (syst), which excludes the CP-conserving hypothesis with a significance of 5.5 standard deviations. In the same sample we find 1139 +/- 49 B0 -> pi+pi- decays and measure the CP-violating asymmetries Spipi = -0.60 +/- 0.11 (stat) +/- 0.03 (syst) and Cpipi = -0.21 +/- 0.09 (stat) +/- 0.02 (syst). CP conservation in B0 -> pi+pi- (Spipi=Cpipi=0) is excluded at a confidence level 1-C.L. = 8 * 10^{-8}, corresponding to 5.4 standard de…

Search for the neutral Higgs bosons of the Minimal Supersymmetric Standard Model in $pp$ collisions at $\sqrt{s}=7$ TeV with the ATLAS detector

A search for neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) is reported. The analysis is based on a sample of proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the Large Hadron Collider. The data were recorded in 2011 and correspond to an integrated luminosity of 4.7 fb[superscript −1] to 4.8 fb[superscript −1]. Higgs boson decays into oppositely-charged muon or τ lepton pairs are considered for final states requiring either the presence or absence of b-jets. No statistically significant excess over the expected background is observed and exclusion limits at the 95% confidence level are derived. The exclusion limits ar…

Measurement of the spin of the Xi(1530) resonance

The properties of the Xi(1530) resonance are investigated in the Lambdac+ --&gt; Xi- pi+ K+ decay process. The data sample was collected with the BaBar detector at the SLAC PEP-II asymmetric-energy e+ e- collider operating at center of mass energies 10.58 and 10.54 GeV. The corresponding integrated luminosity is approximately 230 inverse fb. The spin of the Xi(1530) is established to be 3/2. The existence of an S-wave amplitude in the Xi- pi+ system is inferred, and its interference with the Xi(1530)0 amplitude provides the first clear demonstration of the Breit-Wigner phase motion expected for the Xi(1530). The P_1(cos[theta(Xi-)]) Legendre polynomial moment indicates the presence of a sig…

Measurement of the cross section for top-quark pair production in pp collisions at √s = 7TeV with the ATLAS detector using final states with two high-p(T) leptons

A measurement is reported of the production cross section of top-quark pairs (tt¯) in proton-proton collisions at a center-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC. Candidate events have a signature consistent with containing two isolated leptons, large missing transverse momentum, and at least two jets. Using a data sample corresponding to an integrated luminosity of 0.70 fb−1, a tt¯ production cross section σtt¯=176±5(stat.)+14−11(syst.)±8(lum.) pb is measured for an assumed top-quark mass of mt = 172.5 GeV. This measurement is in good agreement with Standard Model predictions.

Measurements of the branching fractions ofB0→K*0K+K−,B0→K*0π+K−,B0→K*0K+π−, andB0→K*0π+π−

Branching fraction measurements of charmless B{sup 0}{yields}K*{sup 0}h{sub 1}{sup +}h{sub 2}{sup -} (h{sub 1,2}=K, {pi}) decays are presented, using a data sample of 383x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. The results are B(B{sup 0}{yields}K*{sup 0}K{sup +}K{sup -})=(27.5{+-}1.3{+-}2.2)x10{sup -6}, B(B{sup 0}{yields}K*{sup 0}{pi}{sup +}K{sup -})=(4.6{+-}1.1{+-}0.8)x10{sup -6}, and B(B{sup 0}{yields}K*{sup 0}{pi}{sup +}{pi}{sup -})=(54.5{+-}2.9{+-}4.3)x10{sup -6}. The first errors quoted are statistical and the second are systematic. An upper limit is set for B(B{sup 0}{yields}K*{sup 0}K{sup +}{p…

Exclusive initial-state-radiation production of theDD¯,D*D¯, andD*D¯*systems

We perform a study of the exclusive production of in initial-state-radiation events, from e(+)e(-) annihilations at a center-of-mass energy near 10.58 GeV, to search for charmonium and possible new resonances. The data sample corresponds to an integrated luminosity of 384 fb(-1) and was recorded by the BABAR experiment at the PEP-II storage rings. The D (D) over bar, D*(D) over bar, D*(D) over bar* mass spectra show clear evidence of several psi resonances. However, there is no evidence for Y(4260) -> D*(D) over bar or Y(4260) -> D*(D) over bar*.

Study of theDsJ*(2317)+andDsJ(2460)+mesons in inclusivecc¯production nears=10.6  GeV

A study of the $D_{sJ}^*(2317)^+$ and $D_{sJ}(2460)^+$ mesons in inclusive $c\bar{c}$ production is presented using 232~${\rm fb}^{-1}$ of data collected by the BaBar experiment near $\sqrt{s} = 10.6$~\gev. Final states consisting of a $D_s^+$ meson along with one or more $\pi^0$, $\pi^\pm$, or $\gamma$ particles are considered. Estimates of the mass and limits on the width are provided for both mesons and for the $D_{s1}(2536)^+$ meson. A search is also performed for neutral and doubly-charged partners of the $D_{sJ}^*(2317)^+$ meson.

Evidence for the associated production of a W boson and a top quark in ATLAS at √s = 7 TeV

This Letter presents evidence for the associated production of a W boson and a top quark using 2.05 fb[superscript −1] of pp collision data at √s = 7 TeV accumulated with the ATLAS detector at the LHC. The analysis is based on the selection of the dileptonic final states with events featuring two isolated leptons, electron or muon, with significant transverse missing momentum and at least one jet. An approach based on boosted decision trees has been developed to improve the discrimination of single top-quark Wt events from background. A template fit to the final classifier distributions is performed to determine the cross-section. The result is incompatible with the background-only hypothes…

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWF and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; EPLANET, ERC and NSRF, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG and AvH Foundation, Germany; GSRT and NSRF, Greece; ISF, MINERVA, GIF, DIP and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Norway; MNiSW, Poland; GRICES and FCT, Portu…

Dalitz plot analysis ofD0→K¯0K+K−

A Dalitz plot analysis of approximately 12500 D0 events reconstructed in the hadronic decay D0-->K0bar K+ K- is presented. This analysis is based on a data sample of 91.5 fb-1 collected with the BaBar detector at the PEP-II asymmetric-energy e+ e- storage rings at SLAC running at center-of-mass energies on and 40 MeV below the Y4S resonance. The events are selected from e+ e- --> c cbar annihilations using the decay D*+ --> D0 pi+. The following ratio of branching fractions has been obtained: BR = Gamma(D0-->K0bar K+ K-)/Gamma(D0-->K0bar pi+ pi-) = (15.8+/-0.1(stat.)+/-0.5(syst.)x 10-2 Estimates of fractions and phases for resonant and non-resonant contributions to the Dalitz plot are also …

Measurement of the total width, the electronic width, and the mass of theΥ(10580)resonance

We present a measurement of the parameters of the Υ(10580) resonance based on a dataset collected with the BABAR detector at the SLAC PEP-II asymmetric B factory. We measure the total width Γtot=(20.7±1.6±2.5)  MeV, the electronic partial width Γee=(0.321±0.017±0.029)  keV and the mass M=(10579.3±0.4±1.2)  MeV/c2.

Search fortbResonances in Proton-Proton Collisions ats=7  TeVwith the ATLAS Detector

This Letter presents a search for tb resonances in 1.04 fb(-1) of LHC proton-proton collision data collected by the ATLAS detector at a center-of-mass energy of 7 TeV. Events with a lepton, missing transverse momentum, and two jets are selected and the invariant mass of the corresponding final state is reconstructed. The search exploits the shape of the tb invariant mass distribution compared to the expected standard model backgrounds. The model of a right-handed W(R)' with standard model-like couplings is chosen as the benchmark model for this search. No statistically significant excess of events is observed in the data, and upper limits on the cross section times the branching ratio of W(…

Search for Dilepton Resonances inppCollisions ats=7  TeVwith the ATLAS Detector

This Letter reports on a search for narrow high-mass resonances decaying into dilepton final states. The data were recorded by the ATLAS experiment in pp collisions at root s = 7 TeV at the Large Hadron Collider and correspond to a total integrated luminosity of 1.08 (1.21) fb(-1) in the e(+)e(-) (mu(+)mu(-)) channel. No statistically significant excess above the standard model expectation is observed and upper limits are set at the 95% C. L. on the cross section times branching fraction of Z' resonances and Randall-Sundrum gravitons decaying into dileptons as a function of the resonance mass. A lower mass limit of 1.83 TeV on the sequential standard model Z' boson is set. A Randall-Sundrum…

Time-dependent and time-integrated angular analysis ofB→φKS0π0andφK±π∓

We perform a time-dependent and time-integrated angular analysis of the B{sup 0} {yields} {psi}K*(892){sup 0}, {psi}K*{sub 2}(1430{sup 0}), and {psi}(K{pi}){sub S-wave}{sup 0} decays with the final sample of about 465 million B{bar B} pairs recorded with the BABAR detector. Overall, twelve parameters are measured for the vector-vector decay, nine parameters for the vector-tensor decay, and three parameters for the vector-scalar decay, including the branching fractions, CP-violation parameters, and parameters sensitive to final state interaction. We use the dependence on the K{pi} invariant mass of the interference between the scalar and vector or tensor components to resolve discrete ambigu…

Search for high-mass states with one lepton plus missing transverse momentum in proton–proton collisions at s=7 TeV with the ATLAS detector

The ATLAS detector is used to search for high-mass states, such as heavy charged gauge bosons (W', W*) decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 36 pb-1. No excess beyond standard model expectations is observed. A W' with sequential standard model couplings is excluded at 95% confidence level for masses below 1.49 TeV, and a W*(charged chiral boson) for masses below 1.47 TeV.

Improved measurement ofCPobservables inB±→DCP0K±decays

We present a study of the decay B{sup -} {yields} D{sub (CP)}{sup 0}K{sup -} and its charge conjugate, where D{sub (CP)}{sup 0} is reconstructed in both a non-CP flavor eigenstate and in CP (CP-even and CP-odd) eigenstates, based on a sample of 382 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring. We measure the direct CP asymmetries A{sub CP{+-}} and the ratios of the branching fractions R{sub CP{+-}}: A{sub CP+} = 0.27 {+-} 0.09(stat) {+-} 0.04(syst), A{sub CP-} = -0.09 {+-} 0.09(stat) {+-} 0.02(syst), R{sub CP+} = 1.06 {+-} 0.10(stat) {+-} 0.05(syst), R{sub CP-} = 1.03 {+-} 0.10(stat) {+-} 0.05(syst). These resul…

Luminosity determination in pp collisions at s=7 TeV using the ATLAS detector at the LHC

Measurements of luminosity obtained using the ATLAS detector during early running of the Large Hadron Collider (LHC) at s√=7 TeV are presented. The luminosity is independently determined using several detectors and multiple algorithms, each having different acceptances, systematic uncertainties and sensitivity to background. The ratios of the luminosities obtained from these methods are monitored as a function of time and of μ, the average number of inelastic interactions per bunch crossing. Residual time- and μ-dependence between the methods is less than 2% for 0<μ<2.5. Absolute luminosity calibrations, performed using beam separation scans, have a common systematic uncertainty of ±11%, do…

Measurement of the Pseudoscalar Decay ConstantfDsUsing Charm-Tagged Events ine+e−Collisions ats=10.58  GeV

Using 230.2 fb^(-1) of e+e- annihilation data collected with the BABAR detector at and near the peak of the Y(4S) resonance, 489 +/- 55 events containing the pure leptonic decay D_s^+ --> mu^+ nu_mu have been isolated in charm-tagged events. The ratio of partial widths Gamma(D_s^+ --> mu^+ nu_mu)/Gamma(D_s^+ --> phi pi^+) is measured to be 0.143 +/- 0.018 +/- 0.006 allowing a determination of the pseudoscalar decay constant f_{D_s} = (283 +/- 17 +/- 7 +/- 14) MeV. The errors are statistical, systematic, and from the D_s^+ --> phi pi^+ branching ratio, respectively.

Study ofB→X(3872)K, withX(3872)→J/ψπ+π−

We present measurements of the decays B+ -> X(3872) K+ and B0 -> X(3872) K0 with X(3872) -> Jpsi pi+ pi-. The data sample used, collected with the BABAR detector at the PEP-II e+e- asymmetric-energy storage ring, corresponds to 455 x 10^6 BBbar pairs. Branching fraction measurements of BF(B+ -> X(3872) K+) x BF(X(3872) -> Jpsi pi+ pi-) = (8.4 +/- 1.5 +/- 0.7) x 10^{-6} and BF(B0 -> X(3872) K0) x BF(X(3872) -> Jpsi pi+ pi- = (3.5 +/- 1.9 +/- 0.4) x 10^{-6} are obtained. We set an upper limit on the natural width of the X(3872) of Gamma < 3.3 MeV/c^2 at the 90% confidence level.

Measurement of branching fractions andCP-violating charge asymmetries forB-meson decays toD(*)D¯(*), and implications for the Cabibbo-Kobayashi-Maskawa angleγ

We present measurements of the branching fractions and charge asymmetries of B decays to all D^(*)D^(*) modes. Using 232×10^6 BB pairs recorded on the Υ(4S) resonance by the BABAR detector at the e^+e^- asymmetric B factory PEP-II at the Stanford Linear Accelerator Center, we measure the branching fractions B(B^0→D^(*+)D^(*-))=(8.1±0.6±1.0)×10^(-4), B(B^0→D^(*±)D^∓)=(5.7±0.7±0.7)×10^(-4), B(B^0→D^+D^-)=(2.8±0.4±0.5)×10^(-4), B(B^+→D^(*+)D^(*0))=(8.1±1.2±1.2)×10^(-4), B(B^+→D^*+D^0)=(3.6±0.5±0.4)×10^(-4), B(B^+→D^+D^(*0))=(6.3±1.4±1.0)×10^(-4), and B(B^+→D^+D^(0))=(3.8±0.6±0.5)×10^(-4), where in each case the first uncertainty is statistical and the second systematic. We also determine the l…

Search for the decay Bs0→μ+μ− with the ATLAS detector

A blind analysis searching for the decay B-s(0) -> mu(+)mu(-) has been performed using proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC. W ...

Evidence for theηb(1S)Meson in RadiativeΥ(2S)Decay

We have performed a search for the eta_b(1S) meson in the radiative decay of the Upsilon(2S) resonance using a sample of 91.6 million Upsilon(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E_gamma = 610.5 {+4.5} {-4.3} (stat) +/- 1.8 (syst) MeV, corresponding to an eta_b(1S) mass of 9392.9 {+4.6} {-4.8} (stat) +/- 1.9 (syst) MeV/c^2. The branching fraction for the decay Upsilon(2S) --> gamma eta_b(1S) is determined to be (4.2 {+1.1} {-1.0} (stat) +/- 0.9 (syst)) x 10^(-4). The ratio B(Upsilon(2S) --> gamma eta_b(1S))/B(Upsilon(3S) --> gamma eta_b(1S)) = 0.89 {+0.25} {-0.23} (…

Searches for the decaysB0→l±τ∓andB+→l+ν(l=e,μ) using hadronic tag reconstruction

We present searches for the leptonic decays B{sup +} {yields} {ell}{sup +}{nu} and the lepton flavor violating decays B{sup 0} {yields} {ell}{sup {+-}}{tau}{sup {-+}}, where {ell} = e, {mu}, with data collected by the BABAR experiment at SLAC. This search demonstrates a novel technique in which we fully reconstruct the accompanying {bar B} in {Upsilon}(4S) {yields} B{bar B} events, and look for a monoenergetic lepton from the signal B decay. The signal yield is extracted from a fit to the signal lepton candidate momentum distribution in the signal B rest frame. Using a data sample of approximately 378 million B{bar B} pairs (342 fb{sup -1}), we find no evidence of signal in any of the decay…

Bmeson decays to charmless meson pairs containingηorη′mesons

We present updated measurements of the branching fractions for B-0 meson decays to eta K-0, eta eta, eta phi, eta omega, eta K-'(0), eta(')eta('), eta(')phi, and eta(')omega, and branching fractions and CP-violating charge asymmetries for B+ decays to eta pi(+), eta K+, eta(')pi(+), and eta K-'(+). The data represent the full data set of 467x10(6) BB pairs collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at the SLAC National Accelerator Laboratory. Besides large signals for the four charged B decay modes and for B-0 ->eta K-'(0), we find evidence for three B-0 decay modes at greater than 3.0 sigma significance. We find B(B-0 ->eta K-0)=(1.15(-0.38)(+0.43)+…

Search for resonant top quark plus jet production intt¯+jetsevents with the ATLAS detector inppcollisions ats=7  TeV

This paper presents a search for a new heavy particle produced in association with a top or antitop quark. Two models in which the new heavy particle is a color singlet or a color triplet are considered, decaying, respectively, to (t)over-barq or tq, leading to a resonance within the t(t)over-bar + jets signature. The full 2011 ATLAS pp collision data set from the LHC (4.7 fb(-1)) is used to search for t(t)over-bar events produced in association with jets, in which one of the W bosons from the top quarks decays leptonically and the other decays hadronically. The data are consistent with the Standard Model expectation, and a new particle with mass below 430 Gev for both W' boson and color tr…

Observation of the exclusive reactione+e−→ϕηats=10.58  GeV

The authors report the observation of e{sup +}e{sup -} {yields} {phi}{eta} near {radical}s = 10.58 GeV with 6.5 {sigma} significance in the K{sup +}K{sup -}{gamma}{gamma} final state in a data sample of 224 fb{sup -1} collected by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage rings. They measure the restricted radiation-corrected cross section to be {sigma}(e{sup +}e{sup -} {yields} {phi}{eta}) = 2.1 {+-} 0.4(stat) {+-} 0.1(syst) fb within the range |cos{theta}*| < 0.8, where {theta}* is the center-of-mass polar angle of the {phi} meson. The {phi} meson is required to be in the invariant mass range of 1.008 < m{sub {phi}} < 1.035 GeV/c{sup 2}. The radiation corrected cross sec…

Search for rare quark-annihilation decays, B --> Ds(*) Phi

We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and u-bar quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions BF(B- --> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results are consistent with Standard Model expectations.

Characterisation and mitigation of beam-induced backgrounds observed in the ATLAS detector during the 2011 proton-proton run

This paper presents a summary of beam-induced backgrounds observed in the ATLAS detector and discusses methods to tag and remove background contaminated events in data. Triggerrate based monitoring of beam-related backgrounds is presented. The correlations of backgrounds with machine conditions, such as residual pressure in the beam-pipe, are discussed. Results from dedicated beam-background simulations are shown, and their qualitative agreement with data is evaluated. Data taken during the passage of unpaired, i.e. non-colliding, proton bunches is used to obtain background-enriched data samples. These are used to identify characteristic features of beam-induced backgrounds, which then are …

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb[superscript −1] collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutral…

Observation ofe+e−→ρ+ρ−nears=10.58  GeV

We report the first observation of e^+e^- → ρ^+ρ^-, in a data sample of 379 fb^(-1) collected with the BABAR detector at the PEP-II e+e- storage ring at center-of-mass energies near √s = 10:58 GeV. We measure a cross section of σ(e^+e^- → ρ^+ρ^-)= 8:3 ± 0:7(stat)± 0:8(syst) fb within the range of │cosθ^*│ < 0:8 and │ cosθ_±│ < 0:85, where θ^* is the center-of-mass polar angle of the ρ^± meson and θ_± are the angles in the ρ^± rest frame between the direction of the boost from the laboratory frame and the direction of the π^±. Assuming production through single-photon annihilation, there are three independent helicity amplitudes. We measure the ratios of their squared moduli to be │F_(00)│^2…

Observation ofB0→K*0K¯*0and Search forB0→K*0K*0

We report the observation of the b-->d penguin-dominated decay B;{0}-->K;{*0}K[over ];{*0} with a sample of 383.2+/-4.2 million BB[over ] pairs collected with the BABAR detector at the PEP-II asymmetric-energy e;{+}e;{-} collider at the Stanford Linear Accelerator Center. The measured branching fraction is B(B;{0}-->K;{*0}K[over ];{*0})=[1.28_{-0.30};{+0.35}+/-0.11]x10;{-6} and the fraction of longitudinal polarization is f_{L}(B;{0}-->K;{*0}K[over ];{*0})=0.80_{-0.12};{+0.10}+/-0.06. The first error quoted is statistical and the second systematic. We also obtain an upper limit at the 90% confidence level on the branching fraction for B(B;{0}-->K;{*0}K;{*0})<0.41x10;{-6}.

Search for flavor-changing neutral current and lepton-flavor violating decays of D-0 -&gt; l(+)l(-)

We report on a search for the flavor-changing neutral current decays $\Dz\to e^+e^-$ and $\Dz\to\mu^+\mu^-$, and the lepton-flavor violating decay $\Dz\to e^\pm\mu^\mp$. The measurement is based on $122 {fb}^{-1}$ of data collected by the \babar detector at the PEP-II asymmetric $e^+e^-$ collider. No evidence is found for any of the decays. The upper limits on the branching fractions, at the 90 % confidence level, are $1.2\times 10^{-6}$ for $\Dz\to e^+e^-$, $1.3\times 10^{-6}$ for $\Dz\to\mu^+\mu^-$, and $8.1\times 10^{-7}$ for $\Dz\to e^\pm\mu^\mp$.

Measurement of the azimuthal ordering of charged hadrons with the ATLAS detector

This paper presents a study of the possible ordering of charged hadrons in the azimuthal angle relative to the beam axis in high-energy proton-proton collisions at the Large Hadron Collider (LHC). A spectral analysis of correlations between longitudinal and transverse components of the momentum of the charged hadrons, driven by the search for phenomena related to the structure of the QCD field, is performed. Data were recorded with the ATLAS detector at center-of-mass energies of √s=900  GeV and √s=7  TeV. The correlations measured in a kinematic region dominated by low-pT particles are not well described by conventional models of hadron production. The measured spectra show features consis…

Evidence for DirectCPViolation in the Measurement of the Cabbibo-Kobayashi-Maskawa AngleγwithB∓→D(*)K(*)∓Decays

We report the measurement of the Cabibbo-Kobayashi-Maskawa CP-violating angle {gamma} through a Dalitz plot analysis of neutral D meson decays to K{sub S}{sup 0}{pi}{sup +}{pi}{sup -} and K{sub S}{sup 0} K{sup +}K{sup -} produced in the processes B{sup {-+}} {yields} DK{sup {-+}}, B{sup {-+}} {yields} D* K{sup {-+}} with D* {yields} D{pi}{sup 0}, D{gamma}, and B{sup {-+}} {yields} DK*{sup {-+}} with K*{sup {-+}} {yields} K{sub S}{sup 0}{pi}{sup {-+}}, using 468 million B{bar B} pairs collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. We measure {gamma} = (68 {+-} 14 {+-} 4 {+-} 3){sup o} (modulo 180{sup o}), where the first error is statistica…

Measurement of the branching fractions of the radiative charm decaysD0→K¯*0γandD0→ϕγ

We present a measurement of the branching fractions for the Cabibbo-favored radiative decay D^0→K ^(*0) γ and the Cabibbo-suppressed radiative decay D^0→ϕγ. These measurements are based on a data sample corresponding to an integrated luminosity of 387.1  fb^(-1) and recorded with the BABAR detector at the PEP-II e^+e^- asymmetric-energy collider operating at center-of-mass energies 10.58 and 10.54 GeV. We measure the branching fractions relative to the well-studied decay D^0→K^-π^+ and find B(D^0→K ^(*0) γ)/B(D^0→K^-π^+)=(8.43±0.51±0.70)×10^(-3) and B(D^0→ϕγ)/B(D^0→K^-π^+)=(7.15±0.78±0.69)×10^(-4), where the first error is statistical and the second is systematic. This is the first observat…

Measurement of the centrality dependence of the charged particle pseudorapidity distribution in lead–lead collisions at sNN=2.76 TeV with the ATLAS detector

The ATLAS experiment at the LHC has measured the centrality dependence of charged particle pseudorapidity distributions over vertical bar eta vertical bar < 2 in lead-lead collisions at a nucleo ...

Search for dark matter candidates and large extra dimensions in events with a jet and missing transverse momentum with the ATLAS detector

A search for new phenomena in events with a high-energy jet and large missing transverse momentum is performed using data from proton-proton collisions at √s = 7 TeV with the ATLAS experiment at the Large Hadron Collider. Four kinematic regions are explored using a dataset corresponding to an integrated luminosity of 4.7 fb[superscript −1]. No excess of events beyond expectations from Standard Model processes is observed, and limits are set on large extra dimensions and the pair production of dark matter particles.

Measurement of double charmonium production ine+e−annihilations ats=10.6  GeV

We study $e^+e^-\to J/\psi c\bar{c}$ by measuring the invariant mass distribution recoiling against fully reconstructed $J/\psi$ decays, using 124 fb$^{-1}$ of data collected with a center-of-mass energy of 10.6 GeV with the $BaBar$ detector. We observe signals for $\eta_c(1S)$, $\chi_{c0}$, and $\eta_c(2S)$ in the recoil mass distribution, thus confirming previous measurements. We measure $\sigma(e^+e^-\to J/\psi+c\bar{c}) {\cal B} (c\bar{c} \to >2 charged)$ to be $17.6\pm2.8 (stat)^{+1.5}_{-2.1}(syst)$ fb, $ 10.3\pm2.5(stat)^{+1.4}_{-1.8}syst)$ fb, and $16.4\pm3.7(stat)^{+2.4}_{-3.0}(syst)$ fb with $c\bar{c}=\eta_c(1S)$, $\chi_{c0}$, and $\eta_c(2S)$, respectively.

A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20GeV…

Study of resonances in exclusiveBdecays toD¯(*)D(*)K

We present a study of resonances in exclusive decays of $B$ mesons to $\bar{D}^{(*)} D^{(*)} K$. We report the observation of the decays $B \to \Dbar^{(*)} D^+_{s1}(2536)$ where the $D^+_{s1}(2536)$ is reconstructed in the $D^{*0}K^+$ and $D^{*+} K^0_S$ decay channels. We report also the observation of the decays $B \to \psi(3770) K$ where the $\psi(3770)$ decays to $\Dbar^0 D^0$ and $D^- D^+$. In addition, we present the observation of an enhancement for the $\Dbar^{*0} D^0$ invariant mass in the decays $B \to \Dbar^{*0} D^0 K$, at a mass of $(3875.1 {}^{+0.7}_{-0.5} \pm 0.5)$ MeV/$c^2$ with a width of $(3.0 {}^{+1.9}_{-1.4} \pm 0.9)$ MeV (the first errors are statistical and the second ar…

Dalitz plot analysis ofB±→π±π±π∓decays

We present a Dalitz plot analysis of charmless B-+/- decays to the final state pi(+/-)pi(+/-)pi(-/+) using a sample of (465 +/- 5)x10(6) B(B)over bar pairs collected by the BABAR experiment at root s=10.58 GeV. We measure the branching fractions B(B-+/-->pi(+/-)pi(+/-)pi(-/+))=(15.2 +/- 0.6 +/- 1.2 +/- 0.4)x10(-6), B(B-+/-->rho(0)(770)pi(+/-))=(8.1 +/- 0.7 +/- 1.2(-1.1)(+0.4))x10(-6), B(B-+/--> f(2)(1270)pi(+/-))=(1.57 +/- 0.42 +/- 0.16(-0.19)(+0.53))x10(-6), and B(B-+/-->pi(+/-)pi(+/-)pi(-/+) nonresonant)=(5.3 +/- 0.7 +/- 0.6(-0.5)(+1.1))x10(-6), where the uncertainties are statistical, systematic, and model-dependent, respectively. Measurements of branching fractions for the modes B-+/-->…

Observation of the Semileptonic DecaysB→D*τ−ν¯τand Evidence forB→Dτ−ν¯τ

We present measurements of the semileptonic decays B--->D0tau-nutau, B--->D*0tau-nutau, B0-->D+tau-nutau, and B0-->D*+tau-nutau, which are potentially sensitive to non-standard model amplitudes. The data sample comprises 232x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector. From a combined fit to B- and B0 channels, we obtain the branching fractions B(B-->Dtau-nutau)=(0.86+/-0.24+/-0.11+/-0.06)% and B(B-->D*tau-nutau)=(1.62+/-0.31+/-0.10+/-0.05)% (normalized for the B0), where the uncertainties are statistical, systematic, and normalization-mode-related.

Measurement of the branching fractions for inclusiveB−andB¯0decays to flavor-taggedD,Ds, andΛc

We report on the inclusive branching fractions of $B^-$ and of ${\bar B}^0$ mesons decaying to ${D^0 X}$, ${{\bar D}^0 X}$, ${D^+ X}$, ${D^- X}$, ${D_s^+ X}$, ${D_s^- X}$, ${\Lambda_c^+ X}$, ${{\bar \Lambda}_c^- X}$, based on a sample of 88.9 million $B \bar B$ events recorded with the $BABAR$ detector at the $\Upsilon(4S)$ resonance. Events are selected by completely reconstructing one $B$ and searching for a reconstructed charmed particle in the rest of the event. We measure the number of charmed and of anti-charmed particles per $B$ decay and derive the total charm yield per $B^-$ decay, $n_c^- = 1.313 \pm 0.037 \pm 0.062 ^{+0.063}_{-0.042} $, and per ${\bar B}^0$ decay, $n_c^0 = 1.276 \…

Search for Dark Matter Candidates and Large Extra Dimensions in Events with a Photon and Missing Transverse Momentum inppCollision Data ats=7  TeVwith the ATLAS Detector

Measurement of the Spin of the Ω− Hyperon

A measurement of the spin of the Omega(-) hyperon produced through the exclusive process Xi(c)(0)--Omega(-)K(+) is presented using a total integrated luminosity of 116 fb(-1) recorded with the BABAR detector at the e(+)e(-) asymmetric-energy B factory at SLAC. Under the assumption that the Xi(c)(0) has spin 1/2, the angular distribution of the Lambda from Omega(-)--LambdaK(-) decay is inconsistent with all half-integer Omega(-) spin values other than 3/2. Lower statistics data for the process Omega(c)(0)--Omega(-)pi(+) from a 230 fb(-1) sample are also found to be consistent with Omega(-) spin 3/2. If the Xi(c)(0) spin were 3/2, an Omega(-) spin of 5/2 could not be excluded.

Search forB-meson decays to two-body final states witha0(980) mesons

We present a search for B decays to charmless final states involving charged or neutral a0 mesons. The data sample corresponds to 89 million BBbar pairs collected with the BABAR detector operating at the PEP-II asymmetric-energy B Factory at SLAC. We find no significant signals and determine the following 90% C.L. upper limits: BR(B0 -> a0-pi+) a0-K+) a0-K0bar) a00pi+) a00K+) a00K0) a0X and a0 -> etapi, where X indicates K or pi.

Measurement of the isolated diphoton cross section inppcollisions ats=7  TeVwith the ATLAS detector

The ATLAS experiment has measured the production cross section of events with two isolated photons in the final state, in proton-proton collisions at √s=7  TeV. The full data set acquired in 2010 is used, corresponding to an integrated luminosity of 37  pb-1. The background, consisting of hadronic jets and isolated electrons, is estimated with fully data-driven techniques and subtracted. The differential cross sections, as functions of the di-photon mass (mγγ), total transverse momentum (pT,γγ), and azimuthal separation (Δϕγγ), are presented and compared to the predictions of next-to-leading-order QCD.

Search for new particles in two-jet final states in 7 TeV proton-proton collisions with the ATLAS detector at the LHC

19 páginas, 2 figuras, 1 tabla.-- et al.(ATLAS Collaboration).

Search forBmeson decays toη′η′K

We describe searches for decays of B mesons to the charmless final states eta' eta' K. The data consist of 228 million B Bbar pairs produced in e+ e- annihilation, collected with the BaBar detector at the Stanford Linear Accelerator Center. The 90% confidence level upper limits for the branching fractions are Br(B0->eta' eta' K0) eta' eta' K+)<25 10^{-6}.

Search forB→K*νν¯decays

We present a search for the decays B→K^*νν using 454×10^6BB pairs collected at the Υ(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We first select an event sample where one B is reconstructed in a semileptonic or hadronic mode with one charmed meson. The remaining particles in the event are then examined to search for a B→K^*νν decay. The charged K^* is reconstructed as K^*+→K_S^0π^+ or K^(*+)→K^+π^0; the neutral K^* is identified in K^(*0)→K^+π^- mode. We establish upper limits at 90% confidence level of B(B^+→K^(*+)νν)<8×10^(-5), B(B^0→K^(*0)νν)<12×10^(-5), and B(B→K^*νν)<8×10^(-5).

Measurement of the branching fraction and time-dependentCPasymmetry in the decayB0→D*+D*−Ks0

We study the decay B-0 ->(D*+D*-KS0) using (230 +/- 2)x10(6)B (B) over bar pairs collected by the BABAR detector at the PEP-II B factory. We measure a branching fraction B(B-0 ->(D*+D*-KS0))=(4.4 +/- 0.4 +/- 0.7)x10(-3) and find evidence for the decay B-0 -> D*-Ds1+(2536) with a significance of 4.6 sigma. A time-dependent CP asymmetry analysis is also performed to study the possible resonant contributions to B-0 ->(D*+D*-KS0) and the sign of cos2 beta. Our measurement indicates that there is a sizable resonant contribution to the decay B-0 ->(D*+D*-KS0) from an unknown D-s1(+) state with large width, and that cos2 beta is positive at the 94% confidence level under certain theoretical assump…

Dalitz plot analysis of the decay B±→K±K±K∓

We analyze the three-body charmless decay B-+/-->(KKK -/+)-K-+/--K-+/- using a sample of 226.0 +/- 2.5 million B (B) over bar pairs collected by the BABAR detector. We measure the total branching fraction and CP asymmetry to be B=(35.2 +/- 0.9 +/- 1.6)x10(-6) and A(CP)=(-1.7 +/- 2.6 +/- 1.5)%. We fit the Dalitz plot distribution using an isobar model and measure the magnitudes and phases of the decay coefficients. We find no evidence of CP violation for the individual components of the isobar model. The decay dynamics is dominated by the K+K- S-wave, for which we perform a partial-wave analysis in the region m(K+K-)< 2 GeV/c(2). Significant production of the f(0)(980) resonance, and of a sp…

Evidence of a Broad Structure at an Invariant Mass of4.32  GeV/c2in the Reactione+e−→π+π−ψ(2S)Measured atBABAR

The authors measure the cross section for the process e{sup +}e{sup -} {yields} {pi}{sup +}{pi}{sup -}{psi}(2S) from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the PEP-II e{sup +}e{sup -} storage rings. The study is based on 298 fb{sup -1} of data recorded with the BABAR detector. A structure is observed in the cross-section not far above threshold, near 4.32 GeV. This structure is not compatible with the Y(4260) previously reported by this experiment. A single resonance is adequate to describe the cross-section in the low-energy region (< 5.7 GeV).

Measurement and interpretation of moments in inclusive semileptonic decays ¯¯¯B→Xcℓ−¯ν

We present results for the moments of observed spectra in inclusive semileptonic B-meson decays to charm hadrons (B) over bar -> X(c)l(-)(nu) over bar. Moments of the hadronic-mass and the combined mass-and-energy spectra for different minimum electron or muon momenta between 0.8 and 1: 9 GeV/c are obtained from a sample of 232 X 10(6) Gamma(4S) -> B (B) over bar events, collected with the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. We also present a reevaluation of the moments of electron-energy spectra and partial decay fractions B((B) over bar -> X(c)e(-)(nu) over bar) for minimum electron momenta between 0.6 and 1: 5 GeV/c based on a sample of 51 X 10(6) Gamm…

Measurement of inclusive two-particle angular correlations in pp collisions with the ATLAS detector at the LHC

We present a measurement of two-particle angular correlations in proton- proton collisions at s√=900 GeV and 7 TeV. The collision events were collected during 2009 and 2010 with the ATLAS detector at the Large Hadron Collider using a single-arm minimum bias trigger. Correlations are measured for charged particles produced in the kinematic range of transverse momentum pT > 100 MeV and pseudorapidity |η| < 2.5. A complex structure in pseudorapidity and azimuth is observed at both collision energies. Results are compared to pythia 8 and herwig++ as well as to the AMBT2B, DW and Perugia 2011 tunes of pythia 6. The data are not satisfactorily described by any of these models.

Search for Pair Production of a Newb′Quark that Decays into aZBoson and a Bottom Quark with the ATLAS Detector

A search is reported for the pair production of a new quark b' with at least one b' decaying to a Z boson and a bottom quark. The data, corresponding to 2.0 fb(-1) of integrated luminosity, were co ...

Measurement of theB→Xsℓ+ℓ−Branching Fraction with a Sum over Exclusive Modes

We present a preliminary measurement of time-dependent We measure the branching fraction for the flavor-changing neutral-current process B -> Xs l+ l- with a sample of 89 x 10^6 Upsilon(4S) -> BBbar events recorded with the BaBar detector at the PEP-II e+e- storage ring. The final state is reconstructed from e+e- or mu+mu- pairs and a hadronic system consisting of one K or K0s and up to two pions, with at most one pi0. We observe a signal of 40 +/- 10(stat) +/- 2(syst) events and extract the inclusive branching fraction B(B -> Xs l+ l-) = (5.6 +/- 1.5(stat) +/- 0.6(exp syst) +/- 1.1(model syst)) x 10^-6 for mll > 0.2 GeV/c^2.

Measurement of theB0→D*−Ds*+andDs+→ϕπ+branching fractions

The authors present measurements of the branching fractions {Beta}(B{sup 0} {yields} D*{sup -}D*{sub s}{sup +}) and {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}), based on 123 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} B factory. A partial reconstruction technique is used to measure {Beta}(B{sup 0} {yields} D*{sup -}D*{sub s}{sup +}) and the decay chain is fully reconstructed to measure the branching fraction product {Beta}(B{sup 0} {yields} D*{sup -} D*{sub s}{sup +}) x {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}). Comparing these two measurements provides a model-independent determination of …

Study ofe+e−→pp¯via initial-state radiation atBABAR

The e{sup +}e{sup -}{yields}pp cross section is determined over a range of pp masses, from threshold to 4.5 GeV/c{sup 2}, by studying the e{sup +}e{sup -}{yields}pp{gamma} process. The data set corresponds to an integrated luminosity of 232 fb{sup -1}, collected with the BABAR detector at the PEP-II storage ring, at an e{sup +}e{sup -} center-of-mass energy of 10.6 GeV. The mass dependence of the ratio of electric and magnetic form factors, G{sub E}/G{sub M}, is measured for pp masses below 3 GeV/c{sup 2}; its value is found to be significantly larger than 1 for masses up to 2.2 GeV/c{sup 2}. We also measure J/{psi}{yields}pp and {psi}(2S){yields}pp branching fractions and set an upper limi…

Measurement of the Z→ττ cross section with the ATLAS detector

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM

Observation ofΥ(4S)Decays toπ+π−Υ(1S)andπ+π−Υ(2S)

We present the first measurement of Υ(4S) decays to π+π-Υ(1S) and π+π-Υ(2S) based on a sample of 230×106Υ(4S) mesons collected with the BABAR detector. We measure the product branching fractions B(Υ(4S)→π+π-Υ(1S))×B(Υ(1S)→μ+μ-)=(2.23±0.25stat±0.27syst)×10-6 and B(Υ(4S)→π+π-Υ(2S))×B(Υ(2S)→μ+μ-)=(1.69±0.26stat±0.20syst)×10-6, from which we derive the partial widths Γ(Υ(4S)→π+π-Υ(1S))=(1.8±0.4)  keV and Γ(Υ(4S)→π+π-Υ(2S))=(2.7±0.8)  keV.

Measurement of the production cross section forZ/γ*in association with jets inppcollisions ats=7  TeVwith the ATLAS detector

Results are presented on the production of jets of particles in association with a Z/gamma* boson, in proton-proton collisions at root s = 7 TeV with the ATLAS detector. The analysis includes the full 2010 data set, collected with a low rate of multiple proton-proton collisions in the accelerator, corresponding to an integrated luminosity of 36 pb(-1). Inclusive jet cross sections in Z/gamma* events, with Z/gamma* decaying into electron or muon pairs, are measured for jets with transverse momentum p(T) > 30 GeV and jet rapidity vertical bar y vertical bar < 4.4. The measurements are compared to next-to-leading-order perturbative QCD calculations, and to predictions from different Monte Carl…

Measurement of the production cross section of an isolated photon associated with jets in proton-proton collisions ats=7  TeVwith the ATLAS detector

A measurement of the cross section for the production of an isolated photon in association with jets in proton-proton collisions at a center-of-mass energy root s = 7 TeV is presented. Photons are ...

Measurement of theZZProduction Cross Section and Limits on Anomalous Neutral Triple Gauge Couplings in Proton-Proton Collisions ats=7  TeVwith the ATLAS Detector

A measurement of the ZZ production cross section in proton-proton collisions at root s = 7 TeV using data corresponding to an integrated luminosity of 1.02 fb(-1) recorded by the ATLAS experiment a ...

Model-independent search for the decay B^{+}→l^{+}ν_{l}γ

We present a search for the radiative leptonic decay B^+ → l^+ν_lγ, where l = e, μ, using a data sample of 465 × 10^6 BB(overbar) pairs collected by the BABAR experiment. In this analysis, we fully reconstruct the hadronic decay of one of the B mesons in Υ(4S) → B^+B^- decays, then search for evidence of B^+ → l^+ν_lγ in the rest of the event. We observe no significant evidence of signal decays and report model-independent branching fraction upper limits of B(B^+ → e^+ν_eγ) < 17 × 10^(-6), B(B^+ → μ^+ν_μγ) < 24 × 10^(-6), and B(B^+ → l^+ν_lγ) < 15.6 × 10^(-6) (l= e or μ), all at the 90% confidence level.

Study ofB→D(*)Ds(J)(*)decays and measurement ofDs−andDsJ(2460)−branching fractions

We present branching fraction measurements of twelve B meson decays of the form B --> D^(*)D_s(J)^(*). The results are based on Y(4S) decays in BBbar pairs. One of the B mesons is fully reconstructed and the other decays to two charm mesons, of which one is reconstructed, and the mass and momentum of the other is inferred by kinematics. Combining these results with previous exclusive branching fraction measurements, we determine BR(D_s^- --> phi pi^-) = (4.62 +/- 0.36_stat. +/- 0.51_syst.)%, BR(D_sJ(2460)^- --> D_s^*- pi^0) = (56 +/- 13_stat. +/- 9_syst.)% and BR(D-sJ(2460)^- --> D_s^- gamma) = (16 +/- 4_stat. +/- 3_syst.)%.

Measurement of|Vcb|and the Form-Factor Slope inB¯→Dℓ−ν¯ℓDecays in Events Tagged by a Fully ReconstructedBMeson

We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cb vertical bar and the form-factor slope rho(2) in (B) over bar -> Dl(-) (nu) over bar (l) decays based on 460 X 10(6) B (B) over bar events recorded at the Gamma(4S) resonance with the BABAR detector. (B) over bar -> Dl(-) (nu) over bar (l) decays are selected in events in which a hadronic decay of the second B meson is fully reconstructed. We measure B(B- -> D(0)l(-) (nu) over bar (l))/B(B- -> Xl(-) (nu) over bar (l)) = (0.255 +/- 0.009 +/- 0.009) and B((B) over bar (0) -> D(+)l(-) (nu) over bar (l))/B((B) over bar (0) -> Xl(-) (nu) over bar (l)) = (0.230 +/- 0.011 +/- 0.011), along with the different…

Measurement of the Time-DependentCPAsymmetry inB0→DCP(*)h0Decays

We report a measurement of the time-dependent CP-asymmetry parameters S and C in color-suppressed B-0 -> D((*)0)h(0) decays, where h(0) is a pi(0), eta, or omega meson, and the decays to one of the CP eigenstates K+K-, K-S(0)pi(0), or K-S(0)omega. The data sample consists of 383x10(6) Upsilon(4S)-> B (B) over bar decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The results are S=-0.56 +/- 0.23 +/- 0.05 and C=-0.23 +/- 0.16 +/- 0.04, where the first error is statistical and the second is systematic.

Constraints on the CKM angleγinB0→D¯0K*0andB0→D0K*0from a Dalitz analysis ofD0andD¯0decays toKSπ+π−

We present constraints on the angle γ of the unitarity triangle with a Dalitz analysis of neutral D decays to KSπ+π- from the processes B0→D0K*0 (B0→D0K*0) and B0→D0K*0 (B0→D0K*0) with K*0→K+π- (K*0→K-π+). Using a sample of 371×106 BB pairs collected with the BABAR detector at PEP-II, we constrain the angle γ as a function of rS, the magnitude of the average ratio between b→u and b→c amplitudes. © 2009 The American Physical Society.

Measurement of the branching fraction and decay rate asymmetry ofB−→Dπ+π−π0K−

The authors report the observation of the decay B{sup -} {yields} D{sub {pi}{sup +}{pi}{sup -}{pi}{sup 0}}K{sup -}, where D{sub {pi}{sup +}{pi}{sup -}{pi}{sup 0}} indicates a neutral D meson detected in the final state {pi}{sup +}{pi}{sup -}{pi}{sup 0}, excluding K{sub S}{sup 0}{pi}{sup 0}. This doubly Cabibbo-suppressed decay chain can be used to measure the CKM phase {gamma}. Using about 229 million e{sup +}e{sup -} {yields} B{bar B} events recorded by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage ring, they measure the branching fraction {Beta}(B{sup -} {yields} D{sub {pi}{sup +}{pi}{sup -}{pi}{sup 0}K{sup -}}) = (5.5 {+-} 1.0 (stat.) {+-} 0.7 (syst.)) x 10{sup -6} and the …

Further search for supersymmetry ats=7  TeVin final states with jets, missing transverse momentum, and isolated leptons with the ATLAS detector

This work presents a new inclusive search for supersymmetry (SUSY) by the ATLAS experiment at the LHC in proton-proton collisions at a center-of-mass energy root s = 7 TeV in final states with jets, missing transverse momentum and one or more isolated electrons and/or muons. The search is based on data from the full 2011 data-taking period, corresponding to an integrated luminosity of 4.7 fb(-1). Single-lepton and multilepton channels are treated together in one analysis. An increase in sensitivity is obtained by simultaneously fitting the number of events in statistically independent signal regions, and the shapes of distributions within those regions. A dedicated signal region is introduc…

Measurement of theCPAsymmetry inb→sγUsing a Sum of Exclusive Final States

We perform a measurement of the CP asymmetry in b → sγ decays using a sample of 383×10^6 B[overline]B events collected by the BABAR detector at the SLAC PEP-II asymmetric B factory. We reconstruct 16 flavor-specific B decay modes containing a high-energy photon and a hadronic system X_s containing an s quark. We measure the CP asymmetry to be -0.011±0.030(stat)±0.014(syst) for a hadronic system mass between 0.6 and 2.8 GeV/c^2.

Improved measurement of the CKM angleγinB∓→D(*)K(*)∓decays with a Dalitz plot analysis ofDdecays toKS0π+π−andKS0K+K−

We report on an improved measurement of the Cabibbo-Kobayashi-Maskawa CP-violating phase {gamma} through a Dalitz plot analysis of neutral D meson decays to K{sub s}{sup 0}{pi}{sup +}{pi}{sup -} and K{sub s}{sup 0}K{sup +}K{sup -} produced in the processes B{sup {-+}} {yields} DK{sup {-+}}, B{sup {-+}} {yields} D* K{sup {-+}} with D* {yields} D{pi}{sup 0}, D{gamma}, and B{sup {-+}} {yields} DK*{sup {-+}} with K8{sup {-+}} {yields} K{sub S}{sup 0}{pi}{sup {-+}}. Using a sample of 383 million B{bar B} pairs collected by the BABAR detector, we measure {gamma} = (76 {+-} 22 {+-} 5{+-} 5){sup o} (mod 180{sup o}), where the first error is statistical, the second is the experimental systematic unc…

Search for a Light Higgs Boson Decaying to Long-Lived Weakly Interacting Particles in Proton-Proton Collisions ats=7  TeVwith the ATLAS Detector

A search for the decay of a light Higgs boson (120-140 GeV) to a pair of weakly interacting, long-lived particles in 1.94 fb(-1) of proton-proton collisions at root s = 7 TeV recorded in 2011 by the ATLAS detector is presented. The search strategy requires that both long-lived particles decay inside the muon spectrometer. No excess of events is observed above the expected background and limits on the Higgs boson production times branching ratio to weakly interacting, long-lived particles are derived as a function of the particle proper decay length.

Measurement of thee+e−→bb¯Cross Section betweens=10.54and 11.20 GeV

We report e;{+}e;{-}-->bb[over ] cross section measurements by the BABAR experiment performed during an energy scan in the range of 10.54 to 11.20 GeV at the SLAC PEP-II e;{+}e;{-} collider. A total relative error of about 5% is reached in more than 300 center-of-mass energy steps, separated by about 5 MeV. These measurements can be used to derive precise information on the parameters of the Upsilon(10860) and Upsilon(11020) resonances. In particular we show that their widths may be smaller than previously measured.

Search for extra dimensions in diphoton events from proton-proton collisions at root s=7 TeV in the ATLAS detector at the LHC

The large difference between the Planck scale and the electroweak scale, known as the hierarchy problem, is addressed in certain models through the postulate of extra spatial dimensions. A search for evidence of extra spatial dimensions in the diphoton channel has been performed using the full set of proton–proton collisions at √s = 7 TeV recorded in 2011 with the ATLAS detector at the CERN Large Hadron Collider. This dataset corresponds to an integrated luminosity of 4.9fb[superscript −1]. The diphoton invariant mass spectrum is observed to be in good agreement with the Standard Model expectation. In the context of the model proposed by Arkani–Hamed, Dimopoulos and Dvali, 95% confidence le…

Drift Time Measurement in the ATLAS Liquid Argon Electromagnetic Calorimeter using Cosmic Muons

The ionization signals in the liquid argon of the ATLAS electromagnetic calorimeter are studied in detail using cosmic muons. In particular, the drift time of the ionization electrons is measured and used to assess the intrinsic uniformity of the calorimeter gaps and estimate its impact on the constant term of the energy resolution. The drift times of electrons in the cells of the second layer of the calorimeter are uniform at the level of 1.3% in the barrel and 2.8% in the endcaps. This leads to an estimated contribution to the constant term of (0.29-0.04+0.05)% in the barrel and (0.54-0.04+0.06)% in the endcaps. The same data are used to measure the drift velocity of ionization electrons …

Improved measurement of time-dependentCPasymmetries and theCP-odd fraction in the decayB0→D*+D*−

We present an updated measurement of time-dependent CP asymmetries and the CP-odd fraction in the decay B0-->D*+D*- using 232x10(6)BB pairs collected by the BABAR detector at the SLAC PEP-II B factory. We determine the CP-odd fraction to be 0.125+/-0.044(stat)+/-0.007(syst). The time-dependent CP asymmetry parameters C+ and S+ are determined to be 0.06+/-0.17(stat)+/-0.03(syst) and -0.75+/-0.25(stat)+/-0.03(syst), respectively. The standard model predicts these parameters to be 0 and -sin2beta, respectively, in the absence of penguin amplitude contributions.

Observation ofB+→ηρ+and search forB0decays toη′η,ηπ0,η′π0, andωπ0

We present measurements of branching fractions for five B-meson decays to two-body charmless final states. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 459x10{sup 6} BB pairs. The results for branching fractions are, in units of 10{sup -6} (upper limits at 90% C.L.), B(B{sup +}{yields}{eta}{rho}{sup +})=9.9{+-}1.2{+-}0.8, B(B{sup 0}{yields}{eta}{sup '}{eta})=0.5{+-}0.4{+-}0.1(<1.2), B(B{sup 0}{yields}{eta}{pi}{sup 0})=0.9{+-}0.4{+-}0.1(<1.5), B(B{sup 0}{yields}{eta}{sup '}{pi}{sup 0})=0.9{+-}0.4{+-}0.1(<1.5), and B(B{sup 0}{yields}{omega}{pi}{sup 0})=0.07{+-}0.26{+-}0.02(<0.5). The first error quoted is statistical and the second systemati…

Measurement of the W boson polarization in top quark decays with the ATLAS detector

This paper presents measurements of the polarization of W bosons in top quark decays, derived from t¯t events with missing transverse momentum, one charged lepton and at least four jets, or two charged leptons and at least two jets. Data from pp collisions at a centre-of-mass energy of 7 TeV were collected with the ATLAS experiment at the LHC and correspond to an integrated luminosity of 1.04 fb−1. The measured fractions of longitudinally, left- and right-handed polarization are F0 = 0.67 ± 0.07, FL = 0.32 ± 0.04 and FR = 0.01 ± 0.05, in agreement with the Standard Model predictions. As the polarization of the W bosons in top quark decays is sensitive to the Wtb vertex Lorentz structure and…

Search for Radiative Penguin DecaysB+→ρ+γ,B0→ρ0γ, andB0→ωγ

A search for the decays B {yields} {rho}(770){gamma} and B{sup 0} {yields} {omega}(782) is performed on a sample of 211 million {Upsilon}(4S) {yields} B{bar B} events collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. No evidence for the decays is seen. We set the following limits on the individual branching fractions {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) < 1.8 x 10{sup -6}, {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) < 0.4 x 10{sup -6}, and {Beta}(B{sup 0} {yields} {omega}{gamma}) < 1.0 x 10{sup -6} at the 90% confidence level (C.L.). We use the quark model to limit the combined branching fraction {bar {Beta}}[B {yields} ({rho}/{omega})…

Measurements ofe+e−→K+K−η,K+K−π0, andKs0K±π∓cross sections using initial state radiation events

This paper reports measurements of processes: e+e-→γKS0K±π∓, e+e-→γK+K-π0, e+e-→γϕη, and e+e-→γϕπ0. The initial-state radiated photon allows to cover the hadronic final state in the energy range from thresholds up to ≈4.6  GeV. The overall size of the data sample analyzed is 232  fb-1, collected by the BABAR detector running at the PEP-II e+e- storage ring. From the Dalitz plot analysis of the KS0K±π∓ final state, moduli, and relative phase of the isoscalar and the isovector components of the e+e-→KK*(892) cross section are determined. Parameters of ϕ and ρ recurrences are also measured, using a global fitting procedure which exploits the interconnection among amplitudes, moduli, and phases…

Measurement of Branching Fractions and Mass Spectra of B→Kππγ

We present a measurement of the partial branching fractions and mass spectra of the exclusive radiative penguin processes B → K π π γ in the range m K π π < 1.8     GeV / c 2 . We reconstruct four final states: K + π − π + γ , K + π − π 0 γ , K 0 S π − π + γ , and K 0 S π + π 0 γ , where K 0 S → π + π − . Using 232 × 10 6 e + e − → B ¯¯¯ B events recorded by the BABAR experiment at the SLAC PEP-II asymmetric-energy storage ring, we measure the branching fractions B ( B + → K + π − π + γ ) = [ 2.95 ± 0.13 ( stat ) ± 0.20 ( syst ) ] × 10 − 5 , B ( B 0 → K + π − π 0 γ ) = [ 4.07 ± 0.22 ( stat ) ± 0.31 ( syst ) ] × 10 − 5 , B ( B 0 → K 0 π + π − γ ) = [ 1.85 ± 0.21 ( stat ) ± 0.12 ( syst ) ] × …

Search for the rare leptonic decaysB+→l+νl(l=e,μ)

We have performed a search for the rare leptonic decays B+ -> l(+) nu(l)(l = e, mu), using data collected at the Upsilon(4S) resonance by the BABAR detector at the PEP-II storage ring. In a sample of 468 x 10(6) B (B) over bar pairs we find no evidence for a signal and set an upper limit on the branching fractions B(B+ -> mu(+)nu(mu)) e(+) nu(e)) < 1.9 x 10(-6) at the 90% confidence level, using a Bayesian approach.

Observation ofY(3940)→J/ψωinB→J/ψωKatBABAR

We present a study of the decays B;{0,+}-->J/psiomegaK;{0,+} using 383x10;{6} BB[over ] events obtained with the BABAR detector at PEP-II. We observe Y(3940)-->J/psiomega, with mass 3914.6_{-3.4};{+3.8}(stat)+/-2.0(syst) MeV/c;{2}, and width 34_{-8};{+12}(stat)+/-5(syst) MeV. The ratio of B0 and B+ decay to YK is 0.27_{-0.23};{+0.28}(stat)-0.01+0.04(syst), and the relevant B0 and B+ branching fractions are reported.

Improved Measurement ofCPAsymmetries inB0→(cc¯)K0(*)Decays

We present results on time-dependent $CP$ asymmetries in neutral $B$ decays to several $CP$ eigenstates. The measurements use a data sample of about 227 million $\Upsilon$(4S) $\rightarrow B\overline{B}$ decays collected by the BABAR detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. The amplitude of the CP asymmetry, sin2$\Beta$ in the Standard Model, is derived from decay-time distributions from events in which one neutral $B$ meson is fully reconstructed in a final state containing a charmonium meson and the other $B$ meson is determined to be either a $B^0$ or $\overline{B}^0$ from its decay products. We measure sin2$\Beta$ = 0.722 $\pm$ 0.040 (stat.) $\pm$ 0.23 (syst.) in ag…

Observation ofB+→a1+(1260)K0andB0→a1−(1260)K+

We present branching fraction measurements of the decays B(+)-->a(1)(+)(1260)K(0) and B(0)-->a(1)(-)(1260)K(+) with a(1)(+/-)(1260)-->pi(-/+)pi(+/-)pi(+/-). The data sample corresponds to 383 x 10(6) BB pairs produced in e(+)e(-) annihilation through the Upsilon(4S) resonance. We measure the products of the branching fractions B(B(+)-->a(1)(+)(1260)K(0)B(a(1)(+)(1260)-->pi(-)pi(+)pi(+))=(17.4+/-2.5+/-2.2) x 10(-6) and B(B(0)-->a(1)(-)(1260)K(+)B(a(1)(-)(1260)-->pi(+)pi(-)pi(-)) = (8.2+/-1.5+/-1.2) x 10(-6). We also measure the charge asymmetries A(ch)(B(+)-->a(1)(+)(1260)K(0) = 0.12+/-0.11+/-0.02 and A(ch)(B(0)-->a(1)(-)(1260)K+) = -0.16+/-0.12+/-0.01. The first uncertainty quoted is statis…

Observation of the decayB¯0→Λc+p¯π0

In a sample of 467 x 10(6) B (B) over bar pairs collected with the BABAR detector at the PEP- II collider at SLAC we have observed the decay (B) over bar (0) -> Lambda(+)(c)(p) over bar pi(0) and measured the branching fraction to be (1.94 +/- 0.17 +/- 0.14 +/- 0.50 x 10(-4), where the uncertainties are statistical, systematic, and the uncertainty on the Lambda(+)(c) -> pK(-)pi(+) branching fraction, respectively. We determine an upper limit of 1.5 x 10(-6) at 90% C.L. for the product branching fraction B((B) over bar (0) -> Sigma(+)(c) (2455)(p) over bar) x B(Lambda(+)(c) -> pK(-) pi(+)). Furthermore, we observe an enhancement at the threshold of the invariant mass of the baryon- antibaryo…

Measurement of the jet fragmentation function and transverse profile in proton-proton collisions at a center-of-mass energy of 7 TeV with the ATLAS detector

The jet fragmentation function and transverse profile for jets with 25 GeV<pT jet<500 GeV and |ηjet|<1.2 produced in proton–proton collisions with a center-of-mass energy of 7 TeV are presented. The measurement is performed using data with an integrated luminosity of 36 pb−1. Jets are reconstructed and their momentum measured using calorimetric information. The momenta of the charged particle constituents are measured using the tracking system. The distributions corrected for detector effects are compared with various Monte Carlo event generators and generator tunes. Several of these choices show good agreement with the measured fragmentation function. None of these choices reproduce both t…

Study of the exclusive initial-state-radiation production of the D¯¯¯D system

A study of exclusive production of the $D \bar D$ system through initial-state r adiation is performed in a search for charmonium states, where $D=D^0$ or $D^+$. The $D^0$ mesons are reconstructed in the $D^0 \to K^- \pi^+$, $D^0 \to K^- \pi^+ \pi^0$, and $D^0 \to K^- \pi^+ \pi^+ \pi^-$ decay modes. The $D^+$ is reconstructed through the $D^+ \to K^- \pi^+ \pi^+$ decay mode. The analysis makes use of an integrated luminosity of 288.5 fb$^{-1}$ collected by the BaBar experiment. The $D \bar D$ mass spectrum shows a clear $\psi(3770)$ signal. Further structures appear in the 3.9 and 4.1 GeV/$c^2$ regions. No evidence is found for Y(4260) decays to $D \bar D$, implying an up per limit $\frac{\…

Search for heavy neutrinos and right-handed W bosons in events with two leptons and jets in pp collisions at √s=7 TeV with the ATLAS detector

This letter reports on a search for hypothetical heavy neutrinos, N, and right-handed gauge bosons, WR, in events with high transverse momentum objects which include two reconstructed leptons and at least one hadronic jet. The results were obtained from data corresponding to an integrated luminosity of 2.1 fb−1 collected in proton–proton collisions at √s=7 TeV with the ATLAS detector at the CERN Large Hadron Collider. No excess above the Standard Model background expectation is observed. Excluded mass regions for Majorana and Dirac neutrinos are presented using two approaches for interactions that violate lepton and lepton-flavor numbers. One approach uses an effective operator framework, t…

Search for B^{+}→τ^{+}ν

We present a search for the decay B + → τ + ν using 383 × 10 6 B ¯¯¯ B pairs collected at the Υ ( 4 S ) resonance with the BABAR detector at the SLAC PEP-II B -Factory. A sample of events with one reconstructed semileptonic B decay ( B − → D 0 ℓ − ¯ ν ℓ X ) is selected, and in the recoil a search for B + → τ + ν is performed. The τ is identified in the following channels: τ + → e + ν ¯ ν , τ + → μ + ν ¯ ν , τ + → π + ¯ ν , and τ + → π + π 0 ¯ ν . We measure a branching fraction of B ( B + → τ + ν ) = ( 0.9 ± 0.6 ( stat . ) ± 0.1 ( syst . ) ) × 10 − 4 . In the absence of a significant signal, we calculate an upper limit at the 90% confidence level of B ( B + → τ + ν ) < 1.7 × 10 − 4 . We cal…

Study of the decayB¯0→D*+ωπ−

We report on a study of the decay B0bar -> D*+ omega pi- with the BABAR detector at the PEP-II B-factory at the Stanford Linear Accelerator Center. Based on a sample of 232 million BBbar decays, we measure the branching fraction BF(B0bar -> D*+ omega pi-) = (2.88 +/- 0.21(stat.) +/- 0.31(syst.)) \times 10^{-3}. We study the invariant mass spectrum of the omega pi- system in this decay. This spectrum is in good agreement with expectations based on factorization and the measured spectrum in tau- -> omega pi- nu_tau. We also measure the polarization of the D*+ as a function of the omega pi- mass. In the mass region 1.1 to 1.9 GeV we measure the fraction of longitudinal polarization of the D*+ …

Observation of the Bottomonium Ground State in the Decay Υ(3S)→γηb

The authors report the results of a search for the bottomonium ground state {eta}{sub b}(1S) in the photon energy spectrum with a sample of (109 {+-} 1) million of {Upsilon}(3S) recorded at the {Upsilon}(3S) recorded at the {Upsilon}(3S) energy with the BABAR detector at the PEP-II B factory at SLAC. They observe a peak in the photon energy spectrum at E{sub {gamma}} = 921.2{sub -2.8}{sup +2.1}(stat) {+-} 2.4(syst) MeV with a significance of 10 standard deviations. They interpret the observed peak as being due to monochromatic photons from the radiative transition {Upsilon}(3S) {yields} {gamma} {eta}{sub b}(1S). This photon energy corresponds to an {eta}{sub b}(1S) mass of 9388.9{sub -2.3}{…

Search for Dimuon Decays of a Light Scalar Boson in Radiative Transitions Υ→γA0

We search for evidence of a light scalar boson in the radiative decays of the {Upsilon}(2S) and {Upsilon}(3S) resonances: {Upsilon}(2S, 3S) {yields} {gamma}A{sup 0}, A{sup 0} {yields} {mu}{sup +}{mu}{sup -}. Such a particle appears in extensions of the Standaard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. We find no evidence for such processes in the mass range 0.212 {<=} m{sub A{sup 0}} {<=} 9.3 GeV in the samples of 99 x 10{sup 6} {Upsilon}(2S) and 122 x 10{sup 6} {Upsilon}(3S) decays collected by the BABAR detector at the PEP-II B-factory and set stringent upper limits on the effective coupling of the b quark to the A{sup 0}. We also limit the dimuon b…

Searches for Lepton Flavor Violation in the Decaysτ±→e±γandτ±→μ±γ

Searches for lepton-flavor-violating decays of a tau lepton to a lighter mass lepton and a photon have been performed with the entire data set of (963 +/- 7) x 10(6) tau decays collected by the BABAR detector near the Y(4S), Y(3S) and Y(2S) resonances. The searches yield no evidence of signals and we set upper limits on the branching fractions of B(tau(+/-) -> e(+/-)gamma) mu(+/-)gamma) < 4.4 X 10(-8) at 90% confidence level.

Measurement of the branching fractions of the rare decaysB0→Ds(*)+π−,B0→Ds(*)+ρ−, andB0→Ds(*)−K(*)+

The authors report the measurement of the branching fractions of the rare decays B{sup 0} {yields} D{sub s}{sup (*)+} {pi}{sup -}, B{sup 0} {yields} D{sub s}{sup (*)+} {rho}{sup -}, and B{sup 0} {yields} D{sub s}{sup (*)-} K{sup (*)+} in a sample of 381 x 10{sup 6} {Upsilon}(4S) decays into B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. They present evidence for the decay B{sup 0} {yields} D{sub s}{sup -} K*{sup +} and the vector-vector decays B{sup 0} {yields} D{sub s}{sup *+} {rho}{sup -} and B{sup 0} {yields} D{sub s}{sup *-} K{sup *+}, as well as the first measurement of the vector meson polarization in these decays. They …

Search for new phenomena in final states with large jet multiplicities and missing transverse momentum using root s=7 TeV pp collisions with the ATLAS detector

Results are presented of a search for any particle(s) decaying to six or more jets in association with missing transverse momentum. The search is performed using 1.34fb−1 of s √ s = 7 TeV proton-proton collisions recorded by the ATLAS detector during 2011. Data-driven techniques are used to determine the backgrounds in kinematic regions that require at least six, seven or eight jets, well beyond the multiplicities required in previous analyses. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a supersymmetry model (MSUGRA/CMSSM) where they extend previous constraints.

Searches for supersymmetry with the ATLAS detector using final states with two leptons and missing transverse momentum in s=7 TeV proton–proton collisions

Results of three searches are presented for the production of supersymmetric particles decaying into final states with missing transverse momentum and exactly two isolated leptons, e or mu. The analysis uses a data sample collected during the first half of 2011 that corresponds to a total integrated luminosity of 1 fb(-1) of root s = 7 TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider. Opposite-sign and same-sign dilepton events are separately studied, with no deviations from the Standard Model expectation observed. Additionally, in opposite-sign events, a search is made for an excess of same-flavour over different-flavour lepton pairs. Effective pro…

Measurement ofB→XγDecays and Determination of|Vtd/Vts|

Using a sample of 383 million $B\bar{B}$ events collected by the $BaBar$ experiment, we measure sums of seven exclusive final states $B\to X_{d(s)}\gamma$, where $X_d$($X_s$) is a non-strange (strange) charmless hadronic system in the mass range $0.6-1.8$ GeV$/c^2$. After correcting for unmeasured decay modes in this mass range, we obtain a branching fraction for $b \to d \gamma$ of $(7.2\pm 2.7(stat.)\pm 2.3(syst.))\times 10^{-6}$. Taking the ratio of $X_d$ to $X_s$ we find $\Gamma(b \to d \gamma)/\Gamma(b \to s \gamma) = 0.033 \pm 0.013 (stat.) \pm 0.009 (syst.),$ from which we determine $|V_{td}/V_{ts}|=0.177\pm 0.043$.

DirectCP, Lepton Flavor, and Isospin Asymmetries in the DecaysB→K(*)l+l−

We measure branching fractions and integrated rate asymmetries for the rare decays B -> K((*))l(+)l(-), where l(+)l(-) is either e(+)e(-) or mu(+)mu(-), using a sample of 384x10(6) BB events collected with the BABAR detector at the PEP-II e(+)e(-) collider. We find no evidence for direct CP or lepton-flavor asymmetries. However, for dilepton masses below the J/psi resonance, we find evidence for unexpectedly large isospin asymmetries in both B -> Kl(+)l(-) and B -> K(*)l(+)l(-) which differ, respectively, by 3.2 sigma and 2.7 sigma, including systematic uncertainties, from the standard model expectations.

Search for the Rare Decay B→πl+l−

We have performed a search for the flavor-changing neutral-current decays B → π ℓ + ℓ − , where ℓ + ℓ − is either e + e − or μ + μ − , using a sample of 230 × 10 6 Υ ( 4 S ) → B ¯¯¯ B decays collected with the BABAR detector. We observe no evidence of a signal and measure the upper limit on the isospin-averaged branching fraction to be B ( B → π ℓ + ℓ − ) < 9.1 × 10 − 8 at 90% confidence level. We also search for the lepton-flavor-violating decays B → π e ± μ ∓ and measure an upper limit on the isospin-averaged branching fraction of B ( B → π e ± μ ∓ ) < 9.2 × 10 − 8 at 90% confidence level.

Measurement of isolated-photon pair production in pp collisions at root s=7 TeV with the ATLAS detector

The ATLAS experiment at the LHC has measured the production cross section of events with two isolated photons in the final state, in proton-proton collisions at √s = 7 TeV . The full data set collected in 2011, corresponding to an integrated luminosity of 4.9 fb[superscript −1], is used. The amount of background, from hadronic jets and isolated electrons, is estimated with data-driven techniques and subtracted. The total cross section, for two isolated photons with transverse energies above 25 GeV and 22 GeV respectively, in the acceptance of the electromagnetic calorimeter (|η|  0.4, is 44.0[+3.2 over −4.2] pb. The differential cross sections as a function of the di-photon invariant mass, …

Search for WH production with a light Higgs boson decaying to prompt electron-jets in proton–proton collisions at \(\sqrt {s}=7\)  TeV with the ATLAS detector

A search is performed for WH production with a light Higgs boson decaying to hidden-sector particles resulting in clusters of collimated electrons, known as electron-jets. The search is performed with 2.04 fb[superscript −1] of data collected in 2011 with the ATLAS detector at the Large Hadron Collider in proton–proton collisions at √s=7 TeV . One event satisfying the signal selection criteria is observed, which is consistent with the expected background rate. Limits on the product of the WH production cross section and the branching ratio of a Higgs boson decaying to prompt electron-jets are calculated as a function of a Higgs boson mass in the range from 100 to 140 GeV.

Search for Production of Resonant States in the Photon-Jet Mass Distribution UsingppCollisions ats=7  TeVCollected by the ATLAS Detector

This Letter describes a model-independent search for the production of new resonant states in photon + jet events in 2.11 fb(-1) of proton-proton collisions at root s = 7 TeV. We compare the photon ...

e+e−→π+π−π+π−,K+K−π+π−, andK+K−K+K−cross sections at center-of-mass energies 0.5–4.5 GeV measured with initial-state radiation

We study the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-\gamma$, with a hard photon radiated from the initial state. About 60,000 fully reconstructed events have been selected from 89 $fb^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that these data can be compared with the corresponding direct $e^+e^-$ measurements. From the $4\pi$-mass spectrum, the cross section for the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-$ is measured for center-of-mass energies from 0.6 to 4.5 $GeV/c^2$. The uncertainty in the cross section measurement is typically 5%. We also measure the cross sections for the final states $K^+ K^- \pi^+\pi^-$ an…

Limits on the decay-rate difference of neutralBmesons and onCP,T, andCPTviolation inB0B0oscillations

Using events in which one of two neutral-B mesons from the decay of an {Upsilon}(4S) resonance is fully reconstructed, we set limits on the difference between the decay rates of the two neutral-B mass eigenstates and on CP, T, and CPT violation in B{sup 0}{bar B}{sup 0} mixing. The reconstructed decays, comprising both CP and flavor eigenstates, are obtained from 88 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We determine six independent parameters governing oscillations ({Delta}m, {Delta}{Lambda}/{Lambda}), CPT and CP violation (Re z, Im z), and CP and T violation (Im {lambda}{sub CP}, |q/p|), where {la…

Measurement of the relative branching fractions ofB¯→D/D*/D**l−ν¯ldecays in events with a fully reconstructedBmeson

We determine the relative branching fractions of semileptonic B decays to charmed final states. The measurement is performed on the recoil from a fully reconstructed B meson in a sample of 362×106 BB pairs collected at the Υ(4S) resonance with the BABAR detector. A simultaneous fit to a set of discriminating variables is performed on a sample of B→DX-ν decays to determine the contributions from the different channels. We measure Γ(B-→D-ν)/Γ(B-→DX-ν)=0.227±0. 014±0.016, Γ(B-→D*-ν)/Γ(B-→DX- ν)=0.582±0.018±0.030, and Γ(B-→D **-ν)/Γ(B-→DX-ν)=0.191±0. 013±0.019 for the charged B sample, and Γ(B0→D- ν)/Γ(B0→DX-ν)=0.215±0.016±0. 013, Γ(B0→D*-ν)/Γ(B0→DX- ν)=0.537±0.031±0.036, and Γ(B0→ D**-ν)/Γ(B0→…

Study of excited charm-strange baryons with evidence for new baryonsΞc(3055)+andΞc(3123)+

We present a study of excited charm-strange baryon states produced in e{sup +}e{sup -} annihilations at or near a center-of-mass energy of 10.58 GeV, in a data sample with an integrated luminosity of 384 fb{sup -1} recorded with the BABAR detector at the PEP-II e+e storage rings at the Stanford Linear Accelerator Center. We study strong decays of charm-strange baryons to {Lambda}{sub c}{sup +}K{sub S}{sup 0}, {Lambda}{sub c}{sup +}K{sup -}, {Lambda}{sub c}{sup +}K{sup -}{pi}{sup +}, {Lambda}{sub c}{sup +}K{sub S}{sup 0}{pi}{sup -}, {Lambda}{sub c}{sup +}K{sub S}{sup 0}{pi}{sup -}{pi}{sup +}, {Lambda}{sub c}{sup +}K{sup -}{pi}{sup -}{pi}{sup +}. This study confirms the existence of the state…

Measurement ofCPobservables inB±→DCPK±decays and constraints on the CKM angleγ

Using the entire sample of 467×10^6 Υ(4S)→BB[overbar] decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory, we perform an analysis of B^± → DK^± decays, using decay modes in which the neutral D meson decays to either CP-eigenstates or non-CP-eigenstates. We measure the partial decay rate charge asymmetries for CP-even and CP-odd D final states to be A_(CP+) = 0.25±0.06±0.02 and A_(CP-) = -0.09±0.07±0.02, respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter A_(CP+) is different from zero with a significance of 3.6 standard deviations, constituting evidence f…

Search for Supersymmetry Using Final States with One Lepton, Jets, and Missing Transverse Momentum with the ATLAS Detector ins=7  TeVppCollisions

This Letter presents the first search for supersymmetry in final states containing one isolated electron or muon, jets, and missing transverse momentum from sqrt{s} = 7 TeV proton-proton collisions at the LHC. The data were recorded by the ATLAS experiment during 2010 and correspond to a total integrated luminosity of 35 pb-1. No excess above the standard model background expectation is observed. Limits are set on the parameters of the minimal supergravity framework, extending previous limits. For A_0 = 0 GeV, tan beta = 3, mu > 0 and for equal squark and gluino masses, gluino masses below 700 GeV are excluded at 95% confidence level.

Measurement of the absolute branching fractionsB→Dπ,D*π,D**πwith a missing mass method

We present branching fraction measurements of charged and neutral B decays to D{pi}{sup -}, D*{pi}{sup -} and D**{pi}{sup -} with a missing mass method, based on a sample of 231 million {Upsilon}(4S) {yields} B{bar B} pairs collected by the BABAR detector at the PEP-II e{sup +}e{sup -} collider. One of the B mesons is fully reconstructed and the other one decays to a reconstructed charged {pi} and a companion charmed meson identified by its recoil mass, inferred by kinematics. Here D** refers to the sum of all the non-strange charm meson states with masses in the range 2.2-2.8 GeV/c{sup 2}.

Time-integrated and time-dependent angular analyses ofB→J/ψKπ: A measurement ofcos2βwith no sign ambiguity from strong phases

We present results on B -> J/yKp decays using e+e-annihilation data collected with the BABAR detector at the U(4S) resonance. The detector is located at the PEP-II asym.-energy storage ring facility at the Stanford Linear Accelerator Center. Using approx. 88*106 B-B pairs, we measure the decay amplitudes for the flavor eigenmodes and observe strong-phase differences indicative of final-state interactions with a significance of 7.6 std. deviations. We use the interference between the Kp S-wave and P-wave amplitudes in the region of the K*(892) to resolve the ambiguity in the detn. of these strong phases. We then perform an ambiguity-free measurement of cos2b using the angular and time-depend…

Study of hadronic transitions betweenΥstates and observation ofΥ(4S)→ηΥ(1S)decay

We present a study of hadronic transitions between Υ(mS) (m = 4, 3, 2) and Υ(nS) (n = 2, 1) resonances based on 347.5 fb^(-1) of data taken with the BABAR detector at the PEP-II storage rings. We report the first observation of Υ(4S) → ηΥ(1S) decay with a branching fraction [script B](Υ(4S) → ηΥ(1S)) = (1.96±0.06_(stat)±0.09_(syst))×10^(-4) and measure the ratio of partial widths Γ(Υ(4S) → ηΥ(1S))/Γ(Υ(4S) → π^+π^-Υ(1S))=2.41±0.40_(stat)±0.12_(syst). We set 90% CL upper limits on the ratios Γ(Υ(2S) → ηΥ(1S))/Γ(Υ(2S) → π^+π^-Υ(1S))<5.2×10^(-3) and Γ(Υ(3S) → ηΥ(1S))/Γ(Υ (3S) → π^+π^-Υ(1S))<1.9×10^(-2). We also present new measurements of the ratios Γ(Υ(4S) → π^+π^-Υ(2S))/Γ(Υ(4S) → π^+ π^-Υ(1S)…

Properties of jets measured from tracks in proton-proton collisions at center-of-mass energys=7  TeVwith the ATLAS detector

Jets are identified and their properties studied in center-of-mass energy root s = 7 TeV proton-proton collisions at the Large Hadron Collider using charged particles measured by the ATLAS inner detector. Events are selected using a minimum bias trigger, allowing jets at very low transverse momentum to be observed and their characteristics in the transition to high-momentum fully perturbative jets to be studied. Jets are reconstructed using the anti-k(t) algorithm applied to charged particles with two radius parameter choices, 0.4 and 0.6. An inclusive charged jet transverse momentum cross section measurement from 4 GeV to 100 GeV is shown for four ranges in rapidity extending to 1.9 and co…

Observation of Spin Correlation intt¯Events fromppCollisions ats=7  TeVUsing the ATLAS Detector

A measurement of spin correlation in t (t) over bar production is reported using data collected with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 2.1 fb(-1). Candidat ...

Search for Lepton Flavor Violation in the Decayτ±→μ±γ

A search for the nonconservation of lepton flavor number in the decay tau(+/-)->mu(+/-)gamma has been performed using 2.07 x 10(8) e(+)e(-)->tau(+)tau(-) events produced at a center-of-mass energy near 10.58 GeV with the BABAR detector at the PEP-II storage ring. We find no evidence for a signal and set an upper limit on the branching ratio of B(tau(+/-)->mu(+/-)gamma) < 6.8 x 10(-8) at 90% confidence level.

Search for third generation scalar leptoquarks in pp collisions at √s = 7 TeV with the ATLAS detector

A search for pair-produced third generation scalar leptoquarks is presented, using proton-proton collisions at √s = 7 TeV at the LHC. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 4.7 fb[superscript −1]. Each leptoquark is assumed to decay to a tau lepton and a b-quark with a branching fraction equal to 100%. No statistically significant excess above the Standard Model expectation is observed. Third generation leptoquarks are therefore excluded at 95% confidence level for masses less than 534 GeV.

Measurement ofW+W−production inppcollisions ats=7  TeVwith the ATLAS detector and limits on anomalousWWZandWWγcouplings

This paper presents a measurement of the W+W- production cross section in pp collisions at root s = 7 TeV. The leptonic decay channels are analyzed using data corresponding to an integrated luminosity of 4: 6 fb(-1) collected with the ATLAS detector at the Large Hadron Collider. The W+W- production cross section sigma(pp -> W+W- + X) is measured to be 51.9 +/- 2.0(stat) +/- 3.9(syst) +/- 2.0(lumi) pb, compatible with the Standard Model prediction of 44.7(-1.9)(+2.1) pb. A measurement of the normalized fiducial cross section as a function of the leading lepton transverse momentum is also presented. The reconstructed transverse momentum distribution of the leading lepton is used to extract li…

Search forB-meson decays tob1ρandb1K*

We present a search for decays of B mesons to final states with a b(1) meson and a rho or K*(d892) meson. The search is based on a data sample consisting of 465 million B (B) over bar pairs collected by the BABAR detector at the SLAC National Accelerator Laboratory. We do not observe any statistically significant signal. The upper limits we set on the branching fractions range from 1.4 to 8.0 x 10(-6) at the 90% confidence level, including systematic uncertainties.

Measurement of theB0→π−l+νForm-Factor Shape and Branching Fraction, and Determination of|Vub|with a Loose Neutrino Reconstruction Technique

We report the results of a study of the exclusive charmless semileptonic decay, B-0 ->pi(-)center dot(+)nu, undertaken with approximately 227x10(6) BB pairs collected at the Upsilon(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with an innovative loose neutrino reconstruction technique. We obtain partial branching fractions in 12 bins of q(2), the momentum transfer squared, from which we extract the f(+)(q(2)) form-factor shape and the total branching fraction B(B-0 ->pi(-)l(+)nu)=(1.46 +/- 0.07(stat)+/- 0.08(syst))x10(-4). Based on a recent unquenched lattice QCD calculation of the form factor in the range q(2)> 16 GeV2, we f…

Search for lepton flavour violation in the e mu continuum with the ATLAS detector in root s=7 TeV pp collisions at the LHC

This paper presents a search for the t-channel exchange of an R-parity violating scalar top quark ([~ over t] ) in the e[superscript ±]μ[superscript ∓] continuum using 2.1 fb[superscript −1] of data collected by the ATLAS detector in s√=7 TeV pp collisions at the Large Hadron Collider. Data are found to be consistent with the expectation from the Standard Model backgrounds. Limits on R-parity-violating couplings at 95 % C.L. are calculated as a function of the scalar top mass ( m[subscript bar over t]). The upper limits on the production cross section for pp→eμX, through the t-channel exchange of a scalar top quark, ranges from 170 fb for m[subscript ~ over t]=95 GeV to 30 fb for m[subscrip…

Search for heavy vector-like quarks coupling to light quarks in proton–proton collisions at s=7 TeV with the ATLAS detector

This letter presents a search for singly produced vector-like quarks, Q, coupling to light quarks, q. The search is sensitive to both charged current (CC) and neutral current (NC) processes, p p --> Q q --> W q q' and p p --> Q q --> Z q q' with a leptonic decay of the vector gauge boson. In 1.04/fb of data taken in 2011 by the ATLAS experiment at a center-of-mass energy sqrt(s) = 7 TeV, no evidence of such heavy vector-like quarks is observed above the expected Standard Model background. Limits on the heavy vector-like quark production cross section times branching ratio as a function of mass m_Q are obtained. For a coupling kappa_(qQ) = v/m_Q, where v is the Higgs vacuum expectation value…

Search for the decaysB0→e+e−γandB0→μ+μ−γ

We present results of a search for the decays $B^0 \to \ell^+\ell^-\gamma$ ($\ell=e$, $\mu$). The search is performed using $320\times 10^{6}$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the BABAR detector at the PEP-II $B$ Factory at SLAC. We find no significant signal and set the following branching fraction upper limits at the 90% confidence level: $\mathcal{B}(B^0\to e^+e^-\gamma)<1.2\times 10^{-7}$ and $\mathcal{B}(B^0\to \mu^+\mu^-\gamma)<1.5\times 10^{-7}$.

Search for contact interactions in dimuon events fromppcollisions ats=7  TeVwith the ATLAS detector

A search for contact interactions has been performed using dimuon events recorded with the ATLAS detector in proton-proton collisions at root s = 7 TeV. The data sample corresponds to an integrated ...

Search for the rare charmless hadronic decayB+→a0+π0

We present a search for B decays to a charged scalar meson a0+ and a pi0 where the a0+ decays to an eta meson and a pi+. The analysis was performed on a data sample consisting of 383x10-6 BBbar pairs collected with the Babar detector at the PEP-II asymmetric-energy B Factory at SLAC. We find no significant signal and set an upper limit on the product branching fraction BF[(B+ -> a0+ pi0) x (a0+ -> eta pi+)] of 1.4x10-6 at the 90% confidence level.

Charged-particle multiplicities in pp interactions measured with the ATLAS detector at the LHC

Measurements are presented from proton–proton collisions at centre-of-mass energies of \sqrt{s} = 0.9 , 2.36 and 7 TeV recorded with the ATLAS detector at the LHC. Events were collected using a single-arm minimum-bias trigger. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transverse momentum and charged-particle multiplicity are measured. Measurements in different regions of phase space are shown, providing diffraction-reduced measurements as well as more inclusive ones. The observed distributions are corrected to well-defined phase-space regions, using model-independent corrections. The results are compared…

Search for Second-Class Currents inτ−→ωπ−ντ

We report an analysis of tau- decaying into omega.pi-.nu_tau with omega -> pi+pi-pi0 using a data sample containing nearly 320 million tau pairs collected with the BABAR detector at the PEP-II B-Factory. We find no evidence for second-class currents and we set an upper limit of 0.69% at 90% confidence level for the fraction of second-class currents in this decay mode.

Measurement of theB→Xsγbranching fraction and photon energy spectrum using the recoil method

We present a measurement of the branching fraction and photon-energy spectrum for the decay B -> X-s gamma using data from the BABAR experiment. The data sample corresponds to an integrated luminosity of 210 fb(-1), from which approximately 680 000 B (B) over bar events are tagged by a fully reconstructed hadronic decay of one of the B mesons. In the decay of the second B meson, an isolated high-energy photon is identified. We measure B(B -> X-s gamma) = (3.66 +/- 0.85(stat) +/- 0.60(syst)) x 10(-4) for photon energies E-gamma above 1.9 GeV in the B rest frame. From the measured spectrum we calculate the first and second moments for different minimum photon energies, which are used to extra…

Search forB+→D+K0andB+→D+K*0decays

We report a search for the rare decays B^+ → D^+K^0 and B^+ → D^+K^0 in an event sample of approximately 465 x 10^6 BB[overbar] pairs collected with the BABAR detector at the PEP-II asymmetric-energy e^+e^- collider at SLAC National Accelerator Laboratory. We find no significant evidence for either mode and we set 90% probability upper limits on the branching fractions of ℬ(B^+ → D^+K^0) < 2:9 x 10^(-6) and ℬ(B^+ → D^+K*^0) < 3:0 x 10^(-6).

Measurements of neutralBdecay branching fractions toKS0π+π−final states and the charge asymmetry ofB0→K*+π−

Branching fraction measurements using B-meson decays to Kspi+pi- are presented. These measurements were obtained by analyzing a data sample of 88.9 million Y(4S) --> BB decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy B factory. Using a maximum likelihood fit, the following branching fraction results were obtained: Br(B0 -> K0pi+pi- = (43.7 +/- 3.8 +/- 3.4) * 10^-6, Br(B0 --> K{*+}pi-) = (12.9 +/- 2.4 +/- 1.4) * 10$^-6} and Br(B0 --> D-(--> Kspi-)pi+ = (42.7 +/- 2.1 +/- 2.2) * 10^{-6}. The CP violating char ge asymmetry A(K*pi} for the decay B0 --> $K{*+}pi-$ was measured to be A(K*pi} = 0.23 +/- $0.18^{+0.09}_{-0.06}$. For all these measurements the first error…

Readiness of the ATLAS Tile Calorimeter for LHC collisions

67 páginas.-- El PDF es la versión pre-print (arXiv:1007.5423v2).-- The ATLAS Collaboration.-- et al.

Study ofB→πlνandB→ρlνdecays and determination of|Vub|

We present an analysis of exclusive charmless semileptonic B-meson decays based on 377×106 BB pairs recorded with the BABAR detector at the Υ(4S) resonance. We select four event samples corresponding to the decay modes B0→π-l+ν, B+→π0l+ν, B0→ρ-l+ν, and B+→ρ0l+ν and find the measured branching fractions to be consistent with isospin symmetry. Assuming isospin symmetry, we combine the two B→πlν samples, and similarly the two B→ρlν samples, and measure the branching fractions B(B0→π-l+ν)=(1.41±0.05±0.07)×10-4 and B(B0→ρ-l+ν)=(1.75±0.15±0.27)×10-4, where the errors are statistical and systematic. We compare the measured distribution in q2, the momentum transfer squared, with predictions for the…

Observation ofB0→χc0K*0and evidence forB+→χc0K*+

We present the observation of the decay B0 -> chi_c0K*0 as well as evidence of B+ -> chi_c0K*+, with an 8.9 and a 3.6 standard deviation significance, respectively, using a data sample of 454 million Y(4S) -> BB decays collected with the BaBar detector at the PEP-II B meson factory located at the Stanford Linear Accelerator Center (SLAC). The measured branching fractions are: B(B0 -> chi_c0K*0) = (1.7 +/- 0.3 +/- 0.2) * 10^{-4} and B(B+ -> chi_c0K^*+) = (1.4 +/- 0.5 +/- 0.2) * 10^{-4}, where the first quoted errors are statistical and the second are systematic. We obtain a branching fraction upper limit of B(B+ -> chi_c0K*+) < 2.1 * 10^{-4} at the 90% confidence level.

Branching fraction measurements of chargedBdecays toK*+K+K−,K*+π+K−,K*+K+π−andK*+π+π−final states

Branching fraction and asymmetry measurements of charmless B+-> K(*+)h(1)(+)h(2)(-) (where h(1,2)=K, pi) decays are presented, using a data sample of 232x10(6) Upsilon(4S)-> B (B) over bar decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. Using a maximum likelihood fit, the following branching fraction results were obtained: B(B+-> K*+K+K-)=(36.2 +/- 3.3 +/- 3.6)x10(-6) and B(B+-> K*+pi(+)pi(-))=(75.3 +/- 6.0 +/- 8.1)x10(-6). Upper limits were set for B(B+-> K*+pi K-+(-)) K*+K+pi(-)) K*+K+K- and B+-> K*+pi(+)pi(-) were measured to be A(K)(*)KK=0.11 +/- 0.08 +/- 0.03 and A(K)(*)pi pi=0.07 +/- 0.07 +/- 0.04, respectively. The first error quoted on branch…

Measurement of the W±Z production cross section and limits on anomalous triple gauge couplings in proton–proton collisions at s=7 TeV with the ATLAS detector

This Letter presents a measurement of W(+/-)Z production in 1.02 fb(-1) of pp collision data at root s = 7 TeV collected by the ATLAS experiment in 2011. Doubly leptonic decay events are selected w ...

Measurement of the inclusive jet cross-section in pp collisions at $\sqrt{s}=2.76\ \mbox{TeV}$ and comparison to the inclusive jet cross-section at $\sqrt{s} =7\ \mbox{TeV}$ using the ATLAS detector

The inclusive jet cross-section has been measured in proton-proton collisions at sqrt(s)=2.76 TeV in a dataset corresponding to an integrated luminosity of 0.20pb-1 collected with the ATLAS detector at the Large Hadron Collider in 2011. Jets are identified using the anti-kt algorithm with two radius parameters of 0.4 and 0.6. The inclusive jet double-differential cross-section is presented as a function of the jet transverse momentum pT and jet rapidity y, covering a range of 20 &lt;= pT &lt; 430 GeV and |y| &lt; 4.4. The ratio of the cross-section to the inclusive jet cross-section measurement at sqrt(s)=7 TeV, published by the ATLAS Collaboration, is calculated as a function of both trans…

Correlated leading baryon-antibaryon production ine+e−→cc¯→Λc+Λ¯c−X

We present a study of 649 +/- 35 e(+)e(-) -> c (c) over bar events produced at root s approximate to 10.6 GeV containing both Lambda(+)(c) baryon and a (Lambda) over bar (-)(c) antibaryon. The number observed is roughly 4 times that expected if the leading charmed hadron types are uncorrelated, confirming an observation by the CLEO Collaboration. We find a 2-jet topology in these events but very few additional baryons, demonstrating that the primary c and (c) over bar are predominantly contained in a correlated baryon-antibaryon system. In addition to the charmed baryons we observe on average 2.6 +/- 0.2 charged intermediate mesons, predominantly pions, carrying 65% of the remaining energy.

Search for top and bottom squarks from gluino pair production in final states with missing transverse energy and at least three b-jets with the ATLAS detector

This letter reports the results of a search for top and bottom squarks from gluino pair production in 4.7 fb[superscript −1] of pp collisions at s√=7 TeV using the ATLAS detector at the LHC. The search is performed in events with large missing transverse momentum and at least three jets identified as originating from a b-quark. Exclusion limits are presented for a variety of gluino-mediated models with gluino masses up to 1 TeV excluded.

Measurement of Branching Fractions and Charge Asymmetries inBDecays to anηMeson and aK*Meson

We present measurements of branching fractions and charge asymmetries for the decays B-->etaK*, where K* indicates a spin 0, 1, or 2 Kpi system. The data sample corresponds to 344x10(6) BB pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+ e- collider at SLAC. We measure the branching fractions (in units of 10(-6): B(B0-->etaK*0(892))=16.5+/-1.1+/-0.8, B(B+-->etaK*+(892))=18.9+/-1.8+/-1.3, B(B0-->eta(Kpi)0*0)=11.0+/-1.6+/-1.5, B(B+-->eta(Kpi)0*+)=18.2+/-2.6+/-2.6, B(B0-->etaK2*0(1430))=9.6+/-1.8+/-1.1, and B(B+-->etaK2*+(1430))=9.1+/-2.7+/-1.4. We also determine the charge asymmetries for all decay modes.

Search for the DecayB+→K+νν¯

We search for the rare flavor-changing neutral-current decay ${B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}}$ in a data sample of $82\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected with the BABAR detector at the PEP-II $B$-factory. Signal events are selected by examining the properties of the system recoiling against either a reconstructed hadronic or semileptonic charged-$B$ decay. Using these two independent samples we obtain a combined limit of $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{K}^{+}\ensuremath{\nu}\overline{\ensuremath{\nu}})l5.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ at the 90% confidence level. In addition, by…

Study ofB0→π0π0,B±→π±π0, andB±→K±π0decays, and isospin analysis ofB→ππdecays

We present updated measurements of the branching fractions and CP asymmetries for B{sup 0}{yields}{pi}{sup 0}{pi}{sup 0}, B{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup 0}, and B{sup {+-}}{yields}K{sup {+-}}{pi}{sup 0}. Based on a sample of 383x10{sup 6} {upsilon}(4S){yields}BB decays collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, we measure B(B{sup 0}{yields}{pi}{sup 0}{pi}{sup 0})=(1.47{+-}0.25{+-}0.12)x10{sup -6}, B(B{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup 0})=(5.02{+-}0.46{+-}0.29)x10{sup -6}, and B(B{sup {+-}}{yields}K{sup {+-}}{pi}{sup 0})=(13.6{+-}0.6{+-}0.7)x10{sup -6}. We also measure the CP asymmetries C{sub {pi}{sup 0}}{sub {pi}{sup 0}}=-0.49{+-}0.…

Search for lepton flavor violating decays τ±→l± ω

A search for lepton flavor violating decays of a {tau} to a lighter-mass charged lepton and an {omega} vector meson is performed using 384.1 fb{sup -1} of e{sup +}e{sup -} annihilation data collected with the BABAR detector at the Stanford Linear Accelerator Center PEP-II storage ring. No signal is found, and the upper limits on the branching ratios are determined to be {beta}({tau}{sup {+-}} {yields} e{sup {+-}}{omega}) < 1.1 x 10{sup -7} and {beta}({tau}{sup {+-}} {yields} {mu}{sup {+-}}{omega}) < 1.0 x 10{sup -7} at 90% confidence level.

Searches forBMeson Decays toϕϕ,ϕρ,ϕf0(980), andf0(980)f0(980)Final States

We present the results of searches for B decays to charmless final states involving varphi, f_{0}(980), and charged or neutral rho mesons. The data sample corresponds to 384x10;{6} BB[over ] pairs collected with the BABAR detector operating at the PEP-II asymmetric-energy e;{+}e;{-} collider at SLAC. We find no significant signals and determine the following 90% confidence level upper limits on the branching fractions, including systematic uncertainties: B(B;{0}-->varphivarphi) varphirho;{+}) varphirho;{0}) varphif_{0}(980)]xB[f_{0}(980)-->pi;{+}pi;{-}] f_{0}(980)f_{0}(980)]xB[f_{0}(980)-->pi;{+}pi;{-}]xB[f_{0}(980)-->K;{+}K;{-}]<2.3x10;{-7}.

Measurement of theB→πlνBranching Fraction and Determination of|Vub|with TaggedBMesons

We report a measurement of the B ->pi center dot nu branching fraction based on 211 fb(-1) of data collected with the BABAR detector. We use samples of B-0 and B+ mesons tagged by a second B meson reconstructed in a semileptonic or hadronic decay and combine the results assuming isospin symmetry to obtain B(B-0 ->pi(-)center dot(+)nu)=(1.33 +/- 0.17(stat)+/- 0.11(syst))x10(-4). We determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-ub vertical bar by combining the partial branching fractions measured in ranges of the momentum transfer squared and theoretical calculations of the form factor. Using a recent lattice QCD calculation, we find vertical bar V-ub …

Measurement of the branching fraction, polarization, andCPasymmetries inB0→ρ0ρ0decay, and implications for the CKM angleα

We study B^0→ρ^0ρ^0 decays in a sample of 465×10^6 Υ(4S)→BB events collected with the BABAR detector at the PEP-II asymmetric-energy e^+e^- collider located at the Stanford Linear Accelerator Center (SLAC). We measure the branching fraction B=(0.92±0.32±0.14)×10^(-6) and longitudinal polarization fraction f_L=0.75_(-0.14)^(+0.11)±0.05, where the first uncertainty is statistical and the second is systematic. The evidence for the B^0→ρ^0ρ^0 signal has a significance of 3.1 standard deviations, including systematic uncertainties. We investigate the proper-time dependence of the longitudinal component in the decay and measure the CP-violating coefficients S_L^(00)=(0.3±0.7±0.2) and C_L^(00)=(0.…

Branching fractions andCP-violating asymmetries in radiativeBdecays toηKγ

We present measurements of the CP-violation parameters S and C for the radiative decay B^0 → ηK^0_Sγ for B → ηKγ we also measure the branching fractions and for B^+ → ηK^+γ the time-integrated charge asymmetry A_(ch). The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 465 × 10^6 BB pairs produced in e^+e^- annihilation. The results are S = -0.18^(+0.49)_(-0.46) ± 0.12, C = -0.32^(+0.40)_(-0.39) ± 0.07, B(B^0 → ηK^0γ) = (7.1^(+2.1)_(-2.0) ± 0.4) × 10^(-6), B(B^+ → ηK^+γ) = (7.7 ± 1.0 ± 0.4) × 10^(-6), and A_(ch) = (-9.0^(+10.4)_(-9.8) ± 1.4) × 10^(-2). The first error quoted is statistical and the second systematic.

Search for the decayB0→KS0KS0KL0

We present the first search for the decay B0 --> K0_S K0_S K0_L using a data sample of 232 million B Bbar pairs. We find no statistically significant evidence for the non-resonant component of this decay. Our central value for the branching fraction, assuming the true Dalitz distribution is uniform and excluding the phi resonance, is B(B0 --> K0_S K0_S K0_L) = (2.4 +2.7 -2.5 +/- 0.6) x 10^{-6} where the errors are statistical and systematic, respectively. We set a single-sided Bayesian upper limit of B(B0 --> K0_S K0_S K0_L) K0_S K0_S K0_L) < 14 x 10^{-6}.

Evidence forB0→ρ0ρ0Decays and Implications for the Cabibbo-Kobayashi-Maskawa Angleα

We search for the decays B(0) --> rho(0)rho(0), B(0) --> rho(0)f(0)(980), and B(0) --> f(0)(980)f(0)(980) in a sample of about 384 x 10(6) Upsilon(4S) --> BB[over] decays collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at Stanford Linear Accelerator Center. We find evidence for B(0) --> rho(0)rho(0) with 3.5 sigma significance and measure the branching fraction B = (1.07 +/- 0.33 +/- 0.19) x 10(-6) and longitudinal polarization fraction f(L) = 0.87 +/- 0.13 +/- 0.04, where the first uncertainty is statistical, and the second is systematic. The uncertainty on the Cabibbo-Kobayashi-Maskawa quark-mixing matrix unitarity angle alpha due to penguin contributio…

Search for same-sign top-quark production and fourth-generation down-type quarks in pp collisions at √s = 7 TeV with the ATLAS detector

A search is presented for same-sign top-quark production and down-type heavy quarks of charge −1/3 in events with two isolated leptons (e or μ) that have the same electric charge, at least two jets and large missing transverse momentum. The data are selected from pp collisions at √s=7TeV recorded by the ATLAS detector and correspond to an integrated luminosity of 1.04 fb−1. The observed data are consistent with expectations from Standard Model processes. Upper limits are set at 95 % confidence level on the cross section of new sources of same-sign top-quark pair production of 1.4-2.0 pb depending on the assumed mediator mass. Upper limits are also set on the pair-production cross-section fo…

Forward-backward correlations and charged-particle azimuthal distributions in $pp$ interactions using the ATLAS detector

Using inelastic proton-proton interactions at sqrt(s) = 900 GeV and 7 TeV, recorded by the ATLAS detector at the LHC, measurements have been made of the correlations between forward and backward charged-particle multiplicities and, for the first time, between forward and backward charged-particle summed transverse momentum. In addition, jet-like structure in the events is studied by means of azimuthal distributions of charged particles relative to the charged particle with highest transverse momentum in a selected kinematic region of the event. The results are compared with predictions from tunes of the PYTHIA and HERWIG++ Monte Carlo generators, which in most cases are found to provide a r…

Study of theB−→J/ψK−π+π−decay and measurement of theB−→X(3872)K−branching fraction

The authors study the decay B{sup -} {yields} J/{psi}K{sup -}{pi}{sup +}{pi}{sup -} using 117 million B{bar B} events collected at the {Upsilon}(4S) resonance with the BaBar detector at the PEP-II e{sup +}e{sup -} asymmetric-energy storage ring. They measure the branching fractions {Beta}(B{sup -} {yields} J/{psi}K{sup -} {pi}{sup +}{pi}{sup -}) = (116 {+-} 7(stat.) {+-} 9(syst.)) x 10{sup -5} and {Beta}(B{sup -} {yields} X(3872)K{sup -}) x {Beta}(X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -}) = (1.28 {+-} 0.41) x 10{sup -5} and find the mass of the X(3872) to be 3873.4 {+-} 1.4MeV/c{sup 2}. They search for the h{sub c} narrow state in the decay B{sup -} {yields} h{sub c} K{sup -}, h{sub c…

Amplitude Analysis of theB±→φK*(892)±Decay

We perform an amplitude analysis of B-+/-->phi(1020)K-*(892)(+/-) decay with a sample of about 384x10(6) B (B) over bar pairs recorded with the BABAR detector. Overall, twelve parameters are measured, including the fractions of longitudinal f(L) and parity-odd transverse f(perpendicular to) amplitudes, branching fraction, strong phases, and six parameters sensitive to CP violation. We use the dependence on the K pi invariant mass of the interference between the J(P)=1(-) and 0(+) K pi components to resolve the discrete ambiguity in the determination of the strong and weak phases. Our measurements of f(L)=0.49 +/- 0.05 +/- 0.03, f(perpendicular to)=0.21 +/- 0.05 +/- 0.02, and the strong phas…

Determination of the form factors for the decayB0→D*−l+νland of the CKM matrix element|Vcb|

We present a combined measurement of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-cb vertical bar and of the parameters rho(2), R-1(1), and R-2(1), which fully characterize the form factors for the B-0 -> D*(-)center dot(+)nu(center dot) decay in the framework of heavy-quark effective field theory. The results, based on a selected sample of about 52 800 B-0 -> D*(-)center dot(+)nu(center dot) decays, recorded by the BABAR detector, are rho(2)=1.157 +/- 0.094 +/- 0.027, R-1(1)=1.327 +/- 0.131 +/- 0.043, R-2(1)=0.859 +/- 0.077 +/- 0.021, and F(1)vertical bar V-cb vertical bar=(34.7 +/- 0.4 +/- 1.0)x10(-3). The first error is the statistical and the second is the systematic unce…

Evidence for theB0→pp¯K*0andB+→ηcK*+decays and study of the decay dynamics ofBmeson decays intopp¯hfinal states

With a sample of 232x10^6 Upsilon(4S)->BBbar events collected with the BaBar detector, we study the decays of B mesons to ppbarh final states, where h=pi+,Ks,K*0 or K*+. We report evidence for the B->ppbarK*0 decay, with a branching fraction (1.5+/-0.5(stat)+/-0.4(syst))x10^-6, and for the B+->eta_cK*+ decay, with the branching fraction of Br(B+->eta_cK*+)xBr(eta_c->ppbar)=(1.57^{+0.56}_{-0.45}(stat)^{+0.46}_{-0.36}(syst))x10^-6, and provide improved measurements of the branching fractions of the other modes of this type. We also report the measurements of the charge asymmetry consistent with zero in the B+->ppbarpi+, B0->ppbarK*0 and B+->ppbarK*+ modes. No evidence is found for the pentaqu…

Study ofB0→ρ+ρ−decays and constraints on the CKM angleα

We present results from an analysis of B0→ρ+ρ- decays using (383.6±4.2)×106 BB pairs collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The measurements of the B0→ρ+ρ- branching fraction, longitudinal polarization fraction fL, and the CP-violating parameters Slong and Clong are as follows: B(B0→ρ+ρ-)=(25.5±2.1(stat)-3.9+3.6(syst))×10-6, fL=0.992±0.024(stat)-0.013+0.026(syst), Slong=-0.17±0.20(stat)-0. 06+0.05(syst), Clong=0.01±0.15(stat)±0.06(syst). We determine the unitarity triangle angle α, using an isospin analysis of B→ρρ decays. One of the two solutions, α=[73.1,117.0]° at 68% confidence level, is compatible with standard model-based fits of existing da…

Search forB+→τ+νdecays with hadronicBtags

We present a search for the decay B{sup +}{yields}{tau}{sup +}{nu} using 383x10{sup 6} BB pairs collected at the {upsilon}(4S) resonance with the BABAR detector at the SLAC PEP-II B Factory. We select a sample of events with one completely reconstructed tag B in a hadronic decay mode (B{sup -}{yields}D{sup (*)0}X{sup -}), and examine the rest of the event to search for a B{sup +}{yields}{tau}{sup +}{nu} decay. We identify the {tau} lepton in the following modes: {tau}{sup +}{yields}e{sup +}{nu}{nu}, {tau}{sup +}{yields}{mu}{sup +}{nu}{nu}, {tau}{sup +}{yields}{pi}{sup +}{nu}, and {tau}{sup +}{yields}{pi}{sup +}{pi}{sup 0}{nu}. We find a 2.2{sigma} excess in data and measure a branching frac…

Measurements of theτmass and the mass difference of theτ+andτ−atBABAR

We present the result from a precision measurement of the mass of the tau lepton, M-tau, based on 423 fb(-1) of data recorded at the Upsilon(4S) resonance with the BABAR detector. Using a pseudomass endpoint method, we determine the mass to be 1776.68 +/- 0.12(stat)+/- 0.41(syst) MeV. We also measure the mass difference between the tau(+) and tau(-), and obtain (M-tau(+)-M-tau(-))/M-AVG(tau)=(-3.4 +/- 1.3(stat)+/- 0.3(syst))x10(-4), where M-AVG(tau) is the average value of M-tau(+) and M-tau(-).

Search for neutral MSSM Higgs bosons decaying to τ+τ− pairs in proton–proton collisions at s=7 TeV with the ATLAS detector

A search for neutral Higgs bosons decaying to pairs of tau leptons with the ATLAS detector at the LHC is presented. The analysis is based on proton-proton collisions at a center-of-mass energy of 7 TeV, recorded in 2010 and corresponding to an integrated luminosity of 36 pb^-1. After signal selection, 276 events are observed in this data sample. The observed number of events is consistent with the total expected background of 269 +/- 36 events. Exclusion limits at the 95% confidence level are derived for the production cross section of a generic Higgs boson phi as a function of the Higgs boson mass and for A/H/h production in the Minimal Supersymmetric Standard Model (MSSM) as a function of…

Branching Fractions andCPAsymmetries inB0→π0π0,B+→π+π0, andB+→K+π0Decays and Isospin Analysis of theB→ππSystem

We measure the branching fractions and CP asymmetries in the decays B0-->K(+)K(-)K(0)(S) and B+-->K(+)K(0)(S)K(0)(S) using a sample of approximately 122x10(6) BB pairs collected by the BABAR detector. From a time-dependent analysis of the K(+)K(-)K(0)(S) sample that excludes phiK(0)(S), the values of the CP-violation parameters are S=-0.56+/-0.25+/-0.04 and C=-0.10+/-0.19+/-0.10, where the first uncertainty is statistical and the second is systematic. We confirm that the final state is nearly purely CP even and extract the standard model parameter sin(2beta=0.57+/-0.26+/-0.04(+0.17)(-0) where the last error is due to uncertainty on the CP content. We present the first measurement of the CP-…

Observation ofe+e−Annihilation into theC=+1Hadronic Final Statesρ0ρ0andϕρ0

The authors report the first observation of e{sup +}e{sup -} annihilations into states of positive C-parity, namely {rho}{sup 0}{rho}{sup 0} and {phi}{rho}{sup 0}. The two states are observed in the {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} and K{sup +}K{sup -} {pi}{sup +}{pi}{sup -} final states, respectively, in a data sample of 225 fb{sup -1} collected by the BABAR experiment at the PEP-II e{sup +}e{sup -} storage rings at energies near {radical}s = 10.58 GeV. The distributions of cos {theta}*, where {theta}* is the center-of-mass polar angle of the {phi} meson or the forward {rho}{sup 0} meson, suggest production by two-virtual-photon annihilation. They measure cross sections within …

Measurements ofB(B¯0→Λc+p¯)andB(B−→Λc+p¯π−)and studies ofΛc+π−resonances

We present an investigation of the decays B-0 -> Lambda(+)(c)(p) over bar and B- -> Lambda(+)(c)(p) over bar pi(-) based on 383 X 10(6)Y(4S) -> B (B) over bar decays recorded with the BABAR detector. We measure the branching fractions of these decays; their ratio is B(B- -> Lambda(+)(c)(p) over bar pi(-))/B((B) over bar (0) -> Lambda(+)(c)(p) over bar) = 15.4 +/- 1.8 +/- 0.3. The B- -> Lambda(+)(c)(p) over bar pi(-) process exhibits an enhancement at the Lambda(+)(c)(p) over bar threshold and is a laboratory for searches for excited charm baryon states. We observe the resonant decays B- -> Sigma(c)(2455)(0)(p) over bar and B- -> Sigma(c)(2800)(0)(p) over bar but see no evidence for B- -> Si…

Measurement of the Branching Fraction and Photon Energy Moments ofB→XsγandACP(B→Xs+dγ)

The photon spectrum in B -> X-s gamma decay, where X-s is any strange hadronic state, is studied using a data sample of 88.5x10(6) e(+)e(-)->Upsilon(4S)-> B(B) over bar decays collected by the BABAR experiment at the Stanford Linear Accelerator Center. The partial branching fraction, Delta B(B -> X-s gamma)=(3.67 +/- 0.29(stat)+/- 0.34(syst)+/- 0.29(model))x10(-4), the first moment =2.288 +/- 0.025 +/- 0.017 +/- 0.015 GeV, and the second moment =0.0328 +/- 0.0040 +/- 0.0023 +/- 0.0036 GeV2 are measured for the photon energy range 1.9 GeV 1.6 GeV. In addition, the direct CP asymmetry A(CP)(B -> Xs+d gamma) is measured to be -0.110 +/- 0.115(stat)+/- 0.017(syst).

Measurement of the inclusive isolated prompt photon cross section inppcollisions ats=7  TeVwith the ATLAS detector

A measurement of the cross section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy root s = 7 TeV is presented. The measurement covers the pseudorapidity ranges vertical bar eta(gamma)vertical bar < 1: 37 and 1: 52 <= vertical bar eta(gamma)vertical bar < 1: 81 in the transverse energy range 15 <= E-T(gamma) < 100 GeV. The results are based on an integrated luminosity of 880 nb(-1), collected with the ATLAS detector at the Large Hadron Collider. Photon candidates are identified by combining information from the calorimeters and from the inner tracker. Residual background in the selected sample is estimated from data based on the observed d…

Search for displaced muonic lepton jets from light Higgs boson decay in proton–proton collisions at s=7 TeV with the ATLAS detector

A search is performed for collimated muon pairs displaced from the primary vertex produced in the decay of long-lived neutral particles in proton-proton collisions at root s = 7 TeV centre-of-mass ...

Amplitude analysis of the decayD0→K−K+π0

Using 385 fb^-1 of e^+e^- collisions at the CM energies of around 10.6 GeV recorded by the BaBar experiment, we study the amplitudes of the singly Cabibbo-suppressed decay D^0 --> K^- K^+ pi^0. We measure the strong phase difference between the D0bar and D0 decays to the K^*(892)^+ K^- state to be -35.5 +/- 1.9 (stat) +/- 2.2 (syst) degrees, and their amplitude ratio to be 0.599 +/- 0.013 (stat) +/- 0.011 (syst). We observe significant contributions from the Kpi and K^-K^+ scalar and vector amplitudes, and analyze the moments of the cosine of the helicity angle in these systems. We find no evidence for charged, scalar kappa(800) state, nor for higher spin states. We also perform a model-ind…

Measurement of theτ−→ηπ−π+π−ντbranching fraction and a search for a second-class current in theτ−→η′(958)π−ντdecay

The τ-→ηπ-π+π-ντ decay with the η→γγ mode is studied using 384  fb-1 of data collected by the BABAR detector. The branching fraction is measured to be (1.60±0.05±0.11)×10-4. It is found that τ-→f1(1285)π-ντ→ηπ-π+π-ντ is the dominant decay mode with a branching fraction of (1.11±0.06±0.05)×10-4. The first error on the branching fractions is statistical and the second systematic. Note that no particle identification algorithm is applied to the charged tracks to distinguish pions from kaons. In addition, a 90% confidence level upper limit on the branching fraction of the τ-→η′(958)π-ντ decay is measured to be 7.2×10-6. This last decay proceeds through a second-class current and is expected to …

Measurement of theB+→ωl+νandB+→ηl+νbranching fractions

We present a study of the charmless semileptonic B-meson decays B{sup +}{yields}{omega}l{sup +}{nu} and B{sup +}{yields}{eta}l{sup +}{nu}. The analysis is based on 3.83x10{sup 8} BB pairs recorded at the {upsilon}(4S) resonance with the BABAR detector. The {omega} mesons are reconstructed in the channel {omega}{yields}{pi}{sup +}{pi}{sup -}{pi}{sup 0} and the {eta} mesons in the channels {eta}{yields}{pi}{sup +}{pi}{sup -}{pi}{sup 0} and {eta}{yields}{gamma}{gamma}. We measure the branching fractions B(B{sup +}{yields}{omega}l{sup +}{nu})=(1.14{+-}0.16{sub stat}{+-}0.08{sub syst})x10{sup -4} and B(B{sup +}{yields}{eta}l{sup +}{nu})=(0.31{+-}0.06{sub stat}{+-}0.08{sub syst})x10{sup -4}.

Search for excited leptons in proton-proton collisions ats=7  TeVwith the ATLAS detector

The ATLAS detector is used to search for excited leptons in the electromagnetic radiative decay channel l* -> l gamma. Results are presented based on the analysis of pp collisions at a center-of ...

Search forCPviolation in neutralDmeson Cabibbo-suppressed three-body decays

Using 385fb-1 of e+e- collision data collected at center-of-mass energies around 10.6 GeV, we search for time-integrated CP violation in the Cabibbo-suppressed decays D0/D0→π-π+π0 and D0/D0→K-K+π0 with both model-independent and model-dependent methods. Measurements of the asymmetries in amplitudes of flavor states and CP eigenstates provide constraints on theories beyond the standard model, some of which predict CP violation in amplitudes at the 1% level or higher. We find no evidence of CP violation and hence no conflict with the standard model. © 2008 The American Physical Society.

Search forD0−D¯0mixing using semileptonic decay modes

Based on an 87-fb{sup -1} data set collected by the BABAR detector at the PEP-II asymmetric-energy B Factory, a search for D{sup 0}-D-bar{sup 0} mixing has been made using the semileptonic decay modes D*{sup +}{yields}{pi}{sup +}D{sup 0}, D{sup 0}{yields}K{sup (}*{sup )}e{nu} (+c.c.). The use of these modes allows unambiguous flavor tagging and a combined fit of the D{sup 0} decay time and D*{sup +}-D{sup 0} mass difference ({delta}M) distributions. The high-statistics sample of unmixed semileptonic D{sup 0} decays is used to model the {delta}M distribution and time dependence of mixed events directly from the data. Neural networks are used to select events and reconstruct the D{sup 0}. A r…

Measurement of theB−→D0K*−branching fraction

From a sample of 232 million {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector at the PEP-II B Factory in 1999-2004, they measure the B{sup -} {yields} D{sup 0} K*{sup -}(892) decay branching fraction using events where the K*{sup -} is reconstructed in the K{sub S}{sup 0}{pi}{sup -} mode and the D{sup 0} in the K{sup -}{pi}{sup +}, K{sup -}{pi}{sup +}{pi}{sup 0}, and K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -} channels: {Beta}(B{sup -} {yields} D{sup 0}K*{sup -}(892)) = (5.29 {+-} 0.30 (stat) {+-} 0.34 (syst)) x 10{sup -4}.

Measurement of branching fractions and charge asymmetries for exclusive B decays to charmonium

We report measurements of branching fractions and charge asymmetries of exclusive decays of neutral and charged B mesons into two-body final states containing a charmonium state and a light strange meson. The charmonium mesons considered are J/Psi, Psi(2S) and Chi_c1, and the light meson is either K or K*. We use a sample of about 124 million BBbar events collected with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center.

Measurement of t ¯ t production with a veto on additional central jet activity in pp collisions at √ s = 7 TeV using the ATLAS detector

A measurement of the jet activity in t[bar over t] events produced in proton–proton collisions at a centre-of-mass energy of 7 TeV is presented, using 2.05 fb[superscript −1] of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. The t[bar over t] events are selected in the dilepton decay channel with two identified b-jets from the top quark decays. Events are vetoed if they contain an additional jet with transverse momentum above a threshold in a central rapidity interval. The fraction of events surviving the jet veto is presented as a function of this threshold for four different central rapidity interval definitions. An alternate measurement is also perfor…

Improved measurements of the branching fractions forB0→π+π−andB0→K+π−, and a search forB0→K+K−

We present measurements of the branching fractions for the charmless two-body decays B0→π+π- and B0→K+π-, and a search for the decay B0→K+K-. We include the effects of final-state radiation from the daughter mesons for the first time, and quote branching fractions for the inclusive processes B0→h+h′-nγ, where h and h′ are pions or kaons. The maximum value of the sum of the energies of the n undetected photons, Eγmax, is mode-dependent. Using a data sample of approximately 227×106 Υ(4S)→BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we measure: B(B0→π+π-nγ;Eγmax =150MeV)=(5.1±0.4±0.2) ×10-6, B(B0→K+π-nγ;Eγmax =105MeV)=(18.1±0. 6±0.6)×10-6, …

Observation of a Charmed Baryon Decaying toD0pat a Mass Near2.94  GeV/c2

A search for charmed baryons decaying to $D^0 p$ reveals two states: the $\Lambda_c(2880)^+$ baryon and a previously unobserved state at a mass of [$2939.8\pm 1.3 \text{(stat.)}\pm 1.0 \text{(syst.)}$]~\mevcc and with an intrinsic width of [$17.5\pm 5.2 \text{(stat.)}\pm 5.9 \text{(syst.)}$]~\mev. Consistent and significant signals are observed for the $K^-\pi^+$ and $K^-\pi^+\pi^-\pi^+$ decay modes of the $D^0$ in 287 ${\rm fb}^{-1}$ annihilation data recorded by the BaBar detector at a center-of-mass energy of 10.58~${\rm GeV}/c^2$. There is no evidence in the $D^+ p$ spectrum of doubly-charged partners. The mass and intrinsic width of the $\Lambda_c(2880)^+$ baryon and relative yield of …

Measurement ofD0−D¯0mixing using the ratio of lifetimes for the decaysD0→K−π+andK+K−

We present a measurement of ${D}^{0}\mathrm{\text{\ensuremath{-}}}{\overline{D}}^{0}$ mixing and $CP$ violation using the ratio of lifetimes simultaneously extracted from a sample of ${D}^{0}$ mesons produced through the flavor-tagged process ${D}^{*+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}$, where ${D}^{0}$ decays to ${K}^{\ensuremath{\mp}}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, ${K}^{\ensuremath{-}}{K}^{+}$, or ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$, along with the untagged decays ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{\mp}}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ and ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{K}…

Evidence forX(3872)→ψ(2S)γinB±→X(3872)K±Decays and a Study ofB→cc¯γK

In a search for B --> ccbar gamma K decays with the BaBar detector, where ccbar includes J/psi and psi(2S), and K includes K+, Ks, and K*(892), we find evidence for X(3872) --> J/psi gamma and X(3872) --> psi(2S) gamma with 3.6 sigma and 3.5 sigma significance, respectively. We measure the product of branching fractions BR(B+ --> X(3872) K+) x BR(X(3872) --> J/psi gamma) = (2.8 +/- 0.8(stat.) +/- 0.2(syst.)) x 10^(-6) and BR(B+ --> X(3872) K+) x BR(X(3872) --> psi(2S) gamma) = (9.9 +/- 2.9(stat.) +/- 0.6(syst.)) x 10^(-6).

Measurement of ratios of branching fractions andCP-violating asymmetries ofB±→D*K±decays

We report a study of B^± → D^*K^± decays with D^* decaying to Dπ^0 or Dγ, using 383×10^6 B[overline B] pairs collected at the Y(4S) resonance with the BABAR detector at the SLAC PEP-II B Factory. The D meson decays under study include a non-CP mode (K^±π^-/_+), CP-even modes (K^±K^-/_+,π^±π^-/_+), and CP-odd modes (K_S^0π^0,K_S^0φ,K_S^0ω). We measure ratios (R^*_(CP±) of branching fractions of decays to CP eigenmode states and to flavor-specific states as well as CP asymmetries (A^*_(CP±). These measurements are sensitive to the unitarity triangle angle γ. We obtain A_(CP+)^*=-0.11±0.09±0.01, R_(CP+)^*=1.31±0.13±0.04, and A_(CP-)^*=0.06±0.10±0.02, R_(CP-)^*=1.10±0.12±0.04, where the first e…

Search for the rare decaysB+→D(*)+KS0

The authors report on the search for the rare decays B{sup +} {yields} D{sup (*)+} K{sub s}{sup 0} in approximately 226 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEp-II asymmetric-energy B factory at SLAC. They do not observe any significant signal and they set 90% confidence level upper limits on the branching fractions, {Beta}(B{sup +} {yields} D{sup +}K{sup 0}) < 0.5 x 10{sup -5} and {Beta}(B{sup +} {yields} D*{sup +} K{sup 0}) < 0.9 x 10{sup -5}.

Observation ofBmeson decays toωK*and improved measurements forωρandωf0

We present measurements of B meson decays to the final states {omega}K*, {omega}{rho}, and {omega}f{sub 0}, where K* indicates a spin 0, 1, or 2 strange meson. The data sample corresponds to 465 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. B meson decays involving vector-scalar, vector-vector, and vector-tensor final states are analyzed; the latter two shed new light on the polarization of these final states. We measure the branching fractions for nine of these decays; five are observed for the first time. For most decays we also measure the charge asymmetry and, where relevant, the longitudinal polarization f{sub L}.

Observation of Tree-LevelBDecays withss¯Production from Gluon Radiation

We report on our search for decays proceeding via a tree-level b-->c quark transition in which a gluon radiates into an ss[over ] pair. We present observations of the decays B;{-}-->D_{s};{+}K;{-}pi;{-} and B[over ];{0}-->D_{s};{+}K_{S};{0}pi;{-} and evidence for B;{-}-->D_{s};{+}K;{-}K;{-} and set upper limits on the branching fractions for B[over ];{0}-->D_{s};{+}K_{S};{0}pi;{-} and B;{-}-->D_{s};{+}K;{-}K;{-} using 383x10;{6} Upsilon(4S)-->BB[over ] events collected by the BABAR detector at SLAC. We present evidence that the invariant mass distributions of D_{s};{+}K;{-} pairs from B;{-}-->D_{s};{+}K;{-}pi;{-} decays are inconsistent with the phase-space model, suggesting the presence of…

e+e−→K+K−π+π−,K+K−π0π0andK+K−K+K−cross sections measured with initial-state radiation

We study the processes e+e-→K+K-π+π-γ, K+K-π0π0γ and K+K-K+K-γ, where the photon is radiated from the initial state. About 34600, 4400 and 2300 fully reconstructed events, respectively, are selected from 232fb-1 of BABAR data. The invariant mass of the hadronic final state defines the effective e+e- center-of-mass energy, so that the K+K-π+π-γ data can be compared with direct measurements of the e+e-→K+K-π+π- reaction; no direct measurements exist for the e+e-→K+K-π0π0 or e+e-→K+K-K+K- reactions. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution fr…

Measurement ofCPviolation observables and parameters for the decaysB±→DK*±

We study the decay B--> DK*- using a sample of 379x10(6) Upsilon(4S)-> BB events collected with the BABAR detector at the PEP-II B factory. We perform a Gronau-London-Wyler analysis where the D meson decays into either a CP-even (CP+) eigenstate (K+K-, pi(+)pi(-)), CP-odd (CP-) eigenstate (K-S(0)pi(0), K-S(0)phi, K-S(0)omega) or a non-CP state (K-pi(+)). We also analyze D meson decays into K+pi(-) from a Cabibbo-favored D-0 decay or doubly suppressed D-0 decay [Atwood-Dunietz-Soni (ADS) analysis]. We measure observables that are sensitive to the Cabibbo-Kobayashi-Maskawa angle gamma: the partial-rate charge asymmetries A(CP +/-), the ratios R-CP +/- of the B-decay branching fractions in CP …

Measurement of the b-hadron production cross section using decays to D⁎+μ−X final states in pp collisions at s=7 TeV with the ATLAS detector

The b-hadron production cross section is measured with the ATLAS detector in pp collisions at root s = 7 TeV, using 3.3 pb(-1) of integrated luminosity, collected during the 2010 LHC run. The b-had ...

Observation of the Decay B+→K+K−π+

We report the observation of charmless hadronic decays of charged B mesons to the final state K + K − π + . Using a data sample of 347.5     fb − 1 collected at the Υ ( 4 S ) resonance with the BABAR detector, we observe 429 ± 43 signal events with a significance of 9.6 σ . We measure the inclusive branching fraction B ( B + → K + K − π + ) = [ 5.0 ± 0.5 ( stat ) ± 0.5 ( syst ) ] × 10 − 6 . Inspection of the Dalitz plot of signal candidates shows a broad structure peaking near 1.5     GeV / c 2 in the K + K − invariant mass distribution. We find the direct C P asymmetry to be consistent with zero.

Observation of the rare decay B0→KS0K±π∓

We report an analysis of charmless hadronic decays of neutral B mesons to the final state (KSK +/-)-K-0 pi(-/+), using a data sample of (465 +/- 5) x 10(6) B (B) over bar events collected with the BABAR detector at the Gamma(4S) resonance. We observe an excess of signal events with a significance of 5.2 standard deviations including systematic uncertainties and measure the branching fraction to be B(B-0 -> (KSK +/-)-K-0 pi(-/+) (3.2 +/- 0.5 +/- 0.3) x 10(-6), where the uncertainties are statistical and systematic, respectively.

Observation ofB+→b1+K0and search forB-meson decays tob10K0andb1π0

We present the results of searches for decays of B mesons to final states with a b{sub 1} meson and a neutral pion or kaon. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 465x10{sup 6} BB pairs produced in e{sup +}e{sup -} annihilation. The results for the branching fractions are, in units of 10{sup -6}, B(B{sup +}{yields}b{sub 1}{sup +}K{sup 0})=9.6{+-}1.7{+-}0.9, B(B{sup 0}{yields}b{sub 1}{sup 0}K{sup 0})=5.1{+-}1.8{+-}0.5 (<7.8), B(B{sup +}{yields}b{sub 1}{sup +}{pi}{sup 0})=1.8{+-}0.9{+-}0.2 (<3.3), and B(B{sup 0}{yields}b{sub 1}{sup 0}{pi}{sup 0})=0.4{+-}0.8{+-}0.2 (<1.9), with the assumption that B(b{sub 1}{yields}{omega}{pi})=1. We al…

Thee+e−→2(π+π−)π0,2(π+π−)η,K+K−π+π−π0andK+K−π+π−ηcross sections measured with initial-state radiation

We study the processes $e^+ e^-\to 2(\pi^+\pi^-)\pi^0\gamma$, $2(\pi^+\pi^-)\eta\gamma$, $K^+ K^-\pi^+\pi^-\pi^0\gamma$ and $K^+ K^-\pi^+\pi^-\eta\gamma$ with the hard photon radiated from the initial state. About 20000, 4300, 5500 and 375 fully reconstructed events, respectively, are selected from 232 fb$^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective $e^+ e^-$ center-of-mass energy, so that the obtained cross sections from the threshold to about 5 GeV can be compared with corresponding direct \epem measurements, currently available only for the $\eta\pi^+\pi^-$ and $\omega\pi^+\pi^-$ submodes of the $e^+ e^-\to 2(\pi^+\pi^-)\pi^0$ channel. Studyi…

Measurement of the time-dependentCP-violating asymmetry inB0→KS0π0γdecays

We present a measurement of the time-dependent CP-violating asymmetry in B{sup 0} {yields} K*{sup 0}{gamma} decays with K*{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0} based on 232 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. In a sample containing 157 {+-} 16 signal decays, we measure S{sub K*{sup 0}{gamma}} = -0.21 {+-} 0.40 {+-} 0.05 and C{sub K*{sup 0}{gamma}} = -0.40 {+-} 0.23 {+-} 0.03, where the first error is statistical and the second systematic. We also explore B{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0}{gamma} decays with 1.1 < m{sub K{sub S}{sup 0}{pi}{sup 0}} < 1.8 GeV/c{sup 2}…

Search for charged lepton flavor violation in narrow Y decays

Charged-lepton flavor-violating processes are unobservable in the standard model, but they are predicted to be enhanced in several extensions to the standard model, including supersymmetry and models with leptoquarks or compositeness. We present a search for such processes in a sample of 99 × 10 6 Υ ( 2 S ) decays and 117 × 10 6 Υ ( 3 S ) decays collected with the BABAR detector. We place upper limits on the branching fractions B ( Υ ( n S ) → e ± τ ∓ ) and B ( Υ ( n S ) → μ ± τ ∓ ) ( n = 2 , 3 ) at the 10 − 6 level and use these results to place lower limits of order 1 TeV on the mass scale of charged-lepton flavor-violating effective operators.

Search for strong gravity signatures in same-sign dimuon final states using the ATLAS detector at the LHC

A search for microscopic black holes has been performed in a same-sign dimuon final state using 1.3 fb[superscript −1] of proton–proton collision data collected with the ATLAS detector at a centre of mass energy of 7 TeV at the CERN Large Hadron Collider. The data are found to be consistent with the expectation from the Standard Model and the results are used to derive exclusion contours in the context of a low scale gravity model.

Search for Magnetic Monopoles ins=7  TeVppCollisions with the ATLAS Detector

This Letter presents a search for magnetic monopoles with the ATLAS detector at the CERN Large Hadron Collider using an integrated luminosity of 2.0 fb(-1) of pp collisions recorded at a center-of- ...

Precision measurement of the Λ+c baryon mass

The $\Lambda_c^+$ baryon mass is measured using $\Lambda_c^+\to\Lambda K^0_S K^+$ and $\Lambda_c^+\to\Sigma^0 K^0_S K^+$ decays reconstructed in 232 fb$^{-1}$ of data collected with the BaBar detector at the PEP-II asymmetric-energy $e^+e^-$ storage ring. The $\Lambda_c^+$ mass is measured to be $2286.46\pm0.14\mathrm{MeV}/c^2$. The dominant systematic uncertainties arise from the amount of material in the tracking volume and from the magnetic field strength.

Search for Gluinos in Events with Two Same-Sign Leptons, Jets, and Missing Transverse Momentum with the ATLAS Detector in Collisions at

A search is presented for gluinos decaying via the supersymmetric partner of the top quark using events with two same-sign leptons, jets, and missing transverse momentum. The analysis is performed ...

Search for doubly charmed baryonsΞcc+andΞcc++inBABAR

We search for the production of doubly charmed baryons in e(+)e(-) annihilations at or near a center-of-mass energy of 10.58 GeV, in a data sample with an integrated luminosity of 232 fb(-1) recorded with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center. We search for Xi(+)(cc) baryons in the final states Lambda K-+(c)-pi(+) and Xi(0)(c)pi(+), and Xi(++)(cc) baryons in the final states Lambda K-+(c)-pi(+)pi(+) and Xi(0)(c)pi(+)pi(+). We find no evidence for the production of doubly charmed baryons.

Measurements of the Absolute Branching Fractions of B±→K±Xcc̅

We study the two-body decays of ${B}^{\ifmmode\pm\else\textpm\fi{}}$ mesons to ${K}^{\ifmmode\pm\else\textpm\fi{}}$ and a charmonium state ${X}_{c\overline{c}}$ in a sample of $210.5\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data from the BABAR experiment. We perform measurements of absolute branching fractions $\mathcal{B}({B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{K}^{\ifmmode\pm\else\textpm\fi{}}{X}_{c\overline{c}})$ using a missing mass technique, and report several new or improved results. In particular, the upper limit $\mathcal{B}\mathbf{(}{B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{K}^{\ifmmode\pm\else\textpm\fi{}}X(3872)\mathbf{)}l3.2\ifmmode…

Measurement of the cross-section for W boson production in association with b-jets in pp collisions at root s=7 TeV with the ATLAS detector

This paper reports a measurement of the W +b-jets (W +b+ X and W + b[¯ over b] +X) production cross-section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC. These results are based on data corresponding to an integrated luminosity of 4.6 fb[superscript −1], collected with the ATLAS detector. Cross-sections are presented as a function of jet multiplicity and of the transverse momentum of the leading b-jet for both the muon and electron decay modes of the W boson. The W +b-jets cross-section, corrected for all known detector effects, is quoted in a limited kinematic range. Combining the muon and electron channels, the fiducial cross-section for W +b-jets is measured…

Measurements of Charged Current Lepton Universality and|Vus|Using Tau Lepton Decays toe−ν¯eντ,μ−ν¯μντ,π−ντ, andK−ντ

Using 467  fb(-1) of e+e- annihilation data collected with the BABAR detector, we measure (B(τ- → μ- ν(μ) ν(τ)))/(B(τ- → e- ν(e) ν(τ))) =(0.9796±0.0016±0.0036), (B(τ- → π- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.5945±0.0014±0.0061), and (B(τ- → K- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.03882±0.00032±0.00057), where the uncertainties are statistical and systematic, respectively. From these precision τ measurements, we test the standard model assumption of μ-e and τ-μ charge current lepton universality and provide determinations of |Vus| experimentally independent of the decay of a kaon.

Branching fraction andCP-violation charge asymmetry measurements forB-meson decays toηK±,ηπ±,η′K,η′π±,ωK, andωπ±

The authors present measurements of the branching fractions for B{sup 0} meson decays to {eta}{prime}K{sup 0} and {omega}K{sup 0}, and of the branching fractions and CP-violation charge asymmetries for B{sup +} meson decays to {eta}{pi}{sup +}, {eta}K{sup +}, {eta}{prime}{pi}{sup +}, {eta}{prime}K{sup +}, {omega}{pi}{sup +}, and {omega}K{sup +}. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 383 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation. The measurements agree with previous results; they find no evidence for direct CP violation.

Underlying event characteristics and their dependence on jet size of charged-particle jet events inppcollisions at(s)=7  TeVwith the ATLAS detector

Distributions sensitive to the underlying event are studied in events containing one or more charged-particle jets produced in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector at the Large Hadron Collider (LHC). These measurements reflect 800 inverse microbarns of data taken during 2010. Jets are reconstructed using the antikt algorithm with radius parameter R varying between 0.2 and 1.0. Distributions of the charged-particle multiplicity, the scalar sum of the transverse momentum of charged particles, and the average charged-particle pT are measured as functions of pT^JET in regions transverse to and opposite the leading jet for 4 GeV < pT^JET < 100 GeV. In addition, the R-dependen…

Search for a Low-Mass Higgs Boson inΥ(3S)→γA0,A0→τ+τ−atBABAR

We search for a light Higgs boson, $A^0$, in the radiative decay $\Upsilon(3S)\to\gamma A^0$, $A^0\to\tau^+\tau^-$, $\tau^+\to e^+\nu_e \overline{\nu}_{\tau}$ or $\tau^+\to \mu^+ \nu_{\mu} \overline{\nu}_{\tau}$. The data sample contains 122 million $\Upsilon(3S)$ events recorded with the \babar detector. We find no evidence for a narrow structure in the studied $\tau^+\tau^-$ invariant mass region of $4.03(1.5-16)\times 10^{-5}$ across the $m_{\tau^+\tau^-}$ range. We also set a 90% C.L. upper limit on the $\tau^+\tau^-$-decay of the $\eta_b$ at ${\mathcal{B}}(\eta_b\to \tau^+\tau^-)<8%$.

Measurement of the ϒ(1S) production cross-section in pp collisions at s=7 TeV in ATLAS

A measurement of the cross-section for ϒ ( 1 S ) → μ + μ − production in proton–proton collisions at centre of mass energy of 7 TeV is presented. The cross-section is measured as a function of the ϒ ( 1 S ) transverse momentum in two bins of rapidity, | y ϒ ( 1 S ) | 4 GeV and pseudorapidity | η μ | < 2.5 in order to reduce theoretical uncertainties on the acceptance, which depend on the poorly known polarisation. The results are based on an integrated luminosity of 1.13 pb−1, collected with the ATLAS detector at the Large Hadron Collider. The cross-section measurement is compared to theoretical predictions: it agrees to within a factor of two with a prediction based on the NRQCD model incl…

Measurements ofCP-Violating Asymmetries and Branching Fractions inBMeson Decays toη′K

We present measurements of CP-violating asymmetries and branching fractions for the decays B+->omega pi(+), B+->omega K+, and B-0 ->omega K-0. The data sample corresponds to 232x10(6) B (B) over bar pairs produced by e(+)e(-) annihilation at the Upsilon(4S) resonance. For the decay B-0 ->omega K-S(0), we measure the time-dependent CP-violation parameters S=0.51(-0.39)(+0.35)+/- 0.02, and C=-0.55(-0.26)(+0.28)+/- 0.03. We also measure the branching fractions, in units of 10(-6), B(B+->omega pi(+))=6.1 +/- 0.7 +/- 0.4, B(B+->omega K+)=6.1 +/- 0.6 +/- 0.4, and B(B-0 ->omega K-0)=6.2 +/- 1.0 +/- 0.4, and charge asymmetries A(ch)(B+->omega pi(+))=-0.01 +/- 0.10 +/- 0.01 and A(ch)(B+->omega K+)=0…

Search forB0meson decays toπ0KS0KS0,ηKS0KS0, andη′KS0KS0

We describe searches for B{sup 0} meson decays to the charmless final states {pi}{sup 0}K{sub S}{sup 0}K{sub S}{sup 0}, {eta}K{sub S}{sup 0}K{sub S}{sup 0}, and {eta}{prime}K{sub S}{sup 0}K{sub S}{sup 0}. The data sample corresponds to 467 x 10{sup 6} B{bar B} pairs produced in e{sup +}e{sup -} annihilation and collected with the BABAR detector at the SLAC National Accelerator Laboratory. We find no significant signals and determine the 90% confidence level upper limits on the branching fractions, in units of 10{sup -7}, {Beta}(B{sup 0} {yields} {pi}{sup 0}K{sub S}{sup 0}K{sub S}{sup 0}) < 12, {Beta}(B{sup 0} {yields} {eta}K{sub S}{sup 0}K{sub S}{sup 0}) < 10, and {Beta}(B{sup 0} {yields} {…

Search for the decay of aB0orB¯0meson toK¯*0K0orK*0K¯0

We present a search for the decay of a B0 or B0bar meson to a K*0bar K0 or K*0 K0bar final state, using a sample of approximately 232 million BBbar events collected with the BABAR detector at the PEP-II asymmetric energy e+e- collider at SLAC. The measured branching fraction is B(B0 --> K*0bar K0) + B(B0 --> K*0 K0bar) = (0.2+0.9-0.8+0.1-0.3)x 10-6. We obtain the following upper limit for the branching fraction at 90% confidence level: B(B0 --> K*0bar K0) + B(B0 --> K*0 K0bar) phi K0 from sin(2beta).

Determination of the Strange-Quark Density of the Proton from ATLAS Measurements of theW→ℓνandZ→ℓℓCross Sections

AQCD analysis is reported of ATLAS data on inclusive W-+/- and Z boson production in pp collisions at the LHC, jointly with ep deep-inelastic scattering data from HERA. The ATLAS data exhibit sensitivity to the light quark sea composition and magnitude at Bjorken x similar to 0:01. Specifically, the data support the hypothesis of a symmetric composition of the light quark sea at low x. The ratio of the strange-to-down sea quark distributions is determined to be 1:00(-0:28)(+0.25) at absolute four-momentum transfer squared Q(2) = 1: 9 GeV2 and x = 0: 023.

Search for Supersymmetry in Events with Three Leptons and Missing Transverse Momentum ins=7  TeVppCollisions with the ATLAS Detector

A search for the weak production of charginos and neutralinos decaying to a final state with three leptons (electrons or muons) and missing transverse momentum is presented. The analysis uses 2.06 fb(-1) of root s = 7 TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with standard model expectations in two signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric and simplified models. For the simplified models, degenerate lightest chargino and next-to-lightest neutralino masses up to …

Search for scalar top quark pair production in natural gauge mediated supersymmetry models with the ATLAS detector in pp collisions at s=7 TeV

The results of a search for pair production of the lighter scalar partners of top quarks () in 2.05 fb−1 of pp collisions at TeV using the ATLAS experiment at the LHC are reported. Scalar top quar ...

Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using4.7  fb−1ofs=7  TeVproton-proton collision data

A search for squarks and gluinos in final states containing jets, missing transverse momentum and no high-p(T) electrons or muons is presented. The data represent the complete sample recorded in 2011 by the ATLAS experiment in 7 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 4.7 fb(-1). No excess above the Standard Model background expectation is observed. Gluino masses below 860 GeV and squark masses below 1320 GeV are excluded at the 95% confidence level in simplified models containing only squarks of the first two generations, a gluino octet and a massless neutralino, for squark or gluino masses below 2 TeV, respectively. Squarks and glui…

Search for a Supersymmetric Partner to the Top Quark in Final States with Jets and Missing Transverse Momentum ats=7  TeVwith the ATLAS Detector

A search for direct pair production of supersymmetric top squarks ((t) over tilde (1)) is presented, assuming the (t) over tilde (1) decays into a top quark and the lightest supersymmetric particle, (chi) over tilde (0)(1), and that both top quarks decay to purely hadronic final states. A total of 16 (4) events are observed compared to a predicted standard model background of 13.5(-3.6)(+3.7) (4.4(-1.3)(+1.7)) events in two signal regions based on integral Ldt = 4.7 fb(-1) of pp collision data taken at root s = 7 TeV with the ATLAS detector at the LHC. An exclusion region in the (t) over tilde (1) versus (chi) over tilde (0)(1) mass plane is evaluated: 370 1) 10) similar to 0 GeV while m((t…

Measurement of the production cross section of jets in association with a Z boson in pp collisions at $\sqrt{s}$ = 7 TeV with the ATLAS detector

Measurements of the production of jets of particles in association with a Z boson in pp collisions at s√ = 7 TeV are presented, using data corresponding to an integrated luminosity of 4.6 fb[superscript −1] collected by the ATLAS experiment at the Large Hadron Collider. Inclusive and differential jet cross sections in Z events, with Z decaying into electron or muon pairs, are measured for jets with transverse momentum p [subscript T] > 30 GeV and rapidity |y| < 4.4. The results are compared to next-to-leading-order perturbative QCD calculations, and to predictions from different Monte Carlo generators based on leading-order and next-to-leading-order matrix elements supplemented by parton sh…

ATLAS measurements of the properties of jets for boosted particle searches

Measurements are presented of the properties of high transverse momentum jets, produced in proton-proton collisions at a center-of-mass energy of √s=7  TeV. The data correspond to an integrated luminosity of 35  pb−1 and were collected with the ATLAS detector in 2010. Jet mass, width, eccentricity, planar flow and angularity are measured for jets reconstructed using the anti-kt algorithm with distance parameters R=0.6 and 1.0, with transverse momentum pT>300  GeV and pseudorapidity |η|<2. The measurements are compared to the expectations of Monte Carlo generators that match leading-logarithmic parton showers to leading-order, or next-to-leading-order, matrix elements. The generators describ…

Search for a heavy neutral particle decaying into an electron and a muon using 1 fb−1 of ATLAS data

A search is presented for a high mass neutral particle that decays directly to the e±μ∓ final state. The data sample was recorded by the ATLAS detector in s√=7~TeVpp collisions at the LHC from March to June 2011 and corresponds to an integrated luminosity of 1.07 fb−1. The data are found to be consistent with the Standard Model background. The high e±μ∓ mass region is used to set 95% confidence level upper limits on the production of two possible new physics processes: tau sneutrinos in an R-parity violating supersymmetric model and Z′-like vector bosons in a lepton flavor violating model.

Observation of a NewχbState in Radiative Transitions toΥ(1S)andΥ(2S)at ATLAS

The χb(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider at √s=7  TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4  fb-1, these states are reconstructed through their radiative decays to Υ(1S,2S) with Υ→μ+μ-. In addition to the mass peaks corresponding to the decay modes χb(1P,2P)→Υ(1S)γ, a new structure centered at a mass of 10.530±0.005(stat)±0.009(syst)  GeV is also observed, in both the Υ(1S)γ and Υ(2S)γ decay modes. This structure is interpreted as the χb(3P) system.

Measurement of theτ−→K−π0ντbranching fraction

A measurement of the tau(-)-> K-pi(0)nu(tau) branching fraction has been made using 230.2 fb(-1) of data recorded by the BABAR detector at the PEP-II e(+)e(-) collider, located at the Stanford Linear Accelerator Center (SLAC), at a center-of-mass energy root s close to 10.58 GeV. We measure B(tau(-)-> K-pi(0)nu(tau))=(0.416 +/- 0.003(stat)+/- 0.018(syst))%.

Measurement of theD+→π+π0andD+→K+π0branching fractions

We present measurements of the branching fractions for the Cabbibo suppressed decays D+->pi(+)pi(0) and D+-> K+pi(0) based on a data sample corresponding to an integrated luminosity of 124.3 fb(-1). The data were taken with the BABAR detector at the PEP-II B Factory operating on and near the Upsilon(4S) resonance. We find B(D+->pi(+)pi(0))=(1.25 +/- 0.10 +/- 0.09 +/- 0.04)x10(-3) and B(D+-> K+pi(0))=(2.52 +/- 0.47 +/- 0.25 +/- 0.08)x10(-4), where the first uncertainty is statistical, the second systematic and the last error is due to the uncertainties in the absolute branching fraction scale for D+ mesons. This represents the first observation of the doubly Cabibbo-suppressed D+-> K+pi(0) d…

Multi-channel search for squarks and gluinos in root s=7 TeV pp collisions with the ATLAS detector at the LHC

A search for supersymmetric particles in final states with zero, one, and two leptons, with and without jets identified as originating from b-quarks, in 4.7 fb[superscript −1] of √s = 7 TeV pp collisions produced by the Large Hadron Collider and recorded by the ATLAS detector is presented. The search uses a set of variables carrying information on the event kinematics transverse and parallel to the beam line that are sensitive to several topologies expected in supersymmetry. Mutually exclusive final states are defined, allowing a combination of all channels to increase the search sensitivity. No deviation from the Standard Model expectation is observed. Upper limits at 95 % confidence level…

Measurement of the top quark charge in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

A measurement of the top quark electric charge is carried out in the ATLAS experiment at the Large Hadron Collider using 2.05 fb[superscript −1] of data at a centre-of-mass energy of 7 TeV. In units of the elementary electric charge, the top quark charge is determined to be 0.64 ± 0.02 (stat.) ± 0.08 (syst.) from the charges of the top quark decay products in single lepton t[¯ over t] candidate events. This excludes models that propose a heavy quark of electric charge −4/3, instead of the Standard Model top quark, with a significance of more than 8σ.

Search for the decayB0→J/ψγ

We present the results of a search for the radiative decay B0 --> J/psi gamma in a data set containing 123 million Y(4S)--> B B-bar decays, collected by the BABAR detector at the PEP-II asymmetric-energy e+e- storage ring at SLAC. We find no evidence for a signal and place an upper limit of B(B0 --> J/psi gamma) < 1.6 x 10^-6 at 90% confidence level.

Evidence for the decayX(3872)→J/ψω

We present a study of the decays B^(0,+)→J/ψπ^+π^-π^0K^(0,+), using 467×10^6 BB[overbar] pairs recorded with the BABAR detector. We present evidence for the decay mode X(3872)→J/ψω, with product branching fractions B(B^+→X(3872)K^+)×B(X(3872)→J/ψω)=[0.6±0.2(stat)±0.1(syst)]×10^(-5), and B(B^0→X(3872)K^0)×B(X(3872)→J/ψω)=[0.6±0.3(stat)±0.1(syst)]×10^(-5). A detailed study of the π^+π^-π^0 mass distribution from X(3872) decay favors a negative-parity assignment.

Measurement ofB¯0→D(*)0K¯(*)0branching fractions

We present a study of the decays (B) over bar (0)-> D-(*)0(K) over bar ((*)0) using a sample of 226x10(6) Upsilon(4S)-> B (B) over bar decays collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC. We report evidence for the decay of B-0 and (B) over bar (0) mesons to the (DKS0)-K-*0 final state with an average branching fraction B(B-0 ->(DK0)-K-*0)equivalent to(B((B) over bar (0)-> D-*0(K) over bar (0))+B(B-0 ->(DK0)-K-*0))/2=(3.6 +/- 1.2 +/- 0.3)x10(-5). Similarly, we measure B(B-0 ->(DK0)-K-0)equivalent to(B((B) over bar (0)-> D-0(K) over bar (0))+B(B-0 ->(DK0)-K-0))/2=(5.3 +/- 0.7 +/- 0.3)x10(-5) for the (DKS0)-K-0 final state. We measure B((K) over …

Measurements ofCP-Violating Asymmetries in the DecayB0→K+K−K0

The authors analyze the decay B{sup 0} {yields} K{sup +}K{sup -}K{sup 0} using 383 million B{bar B} events collected by the BABAR detector at SLAC to extract CP violation parameter values over the Dalitz plot. Combining all K{sup +}K{sup -}K{sup 0} events, they find A{sub CP} = -0.015 {+-} 0.077 {+-} 0.053 and {beta}{sub eff} = 0.352 {+-} 0.076 {+-} 0.026 rad, corresponding to a CP violation significance of 4.8{sigma}. A second solution near {pi}/2 - {beta}{sub eff} is disfavored with a significance of 4.5{sigma}. They also report A{sub CP} and {beta}{sub eff} separately for decays to {phi}(1020)K{sup 0}, f{sub 0}(980)K{sup 0}, and K{sup +}K{sup -}K{sup 0} with m{sub K{sup +}K{sup -}} > 1.1…

Search for new particles decaying to ZZ using final states with leptons and jets with the ATLAS detector in s=7 TeV proton–proton collisions

A search is presented for a narrow resonance decaying to a pair of Z bosons using data corresponding to 1.02 fb(-1) of integrated luminosity collected by the ATLAS experiment from pp collisions at ...

Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb[superscript −1] of √s = 7 TeV proton-proton collisions

Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb[superscript −1] of pp collision data at √s = 7 TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m [subscript 0], gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits.…

Search forCPviolation and a measurement of the relative branching fraction inD+→K−K+π+decays

We report on a search for the CP asymmetry in the singly Cabibbo-suppressed decays $D^+ \to K^-K^+\pi^+$ and in the resonant decays $D^+ \to \phi\pi^+$ and $D^+ \to \overline{K}^{\star0}K^+$ based on a data sample of 79.9 fb$^{-1}$ recorded by the BABAR detector. We use the Cabibbo-favored $D_s^+ \to K^-K^+\pi^+$ branching fraction as normalization in the measurements to reduce systematic uncertainties. The CP asymmetries obtained are $A_{CP}(K^-K^+\pi^{\pm}) = (1.4 \pm 1.0 (stat.) \pm 0.8 (syst.) \times 10^{-2}, A_{CP}(phi pi) = (0.2 +/- 1.5 (stat.) +/- 0.6 (syst.) x 10^-2$, and $A_{CP}(\overline{K}^{\star0} K^{\pm}) = (0.9 \pm 1.7 (stat.) \pm 0.7 (syst.) \times 10^{-2}$. The relative bran…

Measurement ofCPViolation Parameters with a Dalitz Plot Analysis ofB±→Dπ+π−π0K±

We report the results of a CP violation analysis of the decay B-+/- -> D pi+pi(-)pi K-0(+/-), where D-pi(+)pi(-)pi(0) indicates a neutral D meson detected in the final state pi(+)pi(-)pi(0), excluding K-S(0)pi(0). The analysis makes use of 324x10(6) e(+)e -> B (B) over bar events recorded by the BABAR experiment at the PEP-II e(+)e(-) storage ring. Analyzing the pi(+)pi(-)pi(0) Dalitz plot distribution and the B-+/- -> D-pi(+)pi(-)pi K-0(+/-) branching fraction and decay rate asymmetry, we find the following one-standard-deviation constraints on the amplitude ratio and on the weak and strong phases: 0.06 pi(+)pi(-)pi(0) decay amplitude.

Measurements of branching fractions, polarizations, and directCP-violation asymmetries inB+→ρ0K*+andB+→f0(980)K*+decays

We report searches for B-meson decays to the charmless final states rho K* and f0(980) K* with a sample of 232 million BBbar pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We measure the following branching fractions in units of 10^{-6}: B (B+ --> rho0 K*+) = 3.6 +/- 1.7 +/- 0.8 ( rho+ K*0) = 9.6 +/- 1.7 +/- 1.5, B (B0 --> rho- K*+) = 5.4 +/- 3.6 +/- 1.6 ( rho0 K*0) = 5.6 +/- 0.9 +/- 1.3, B (B+ --> f0(980) K*+) = 5.2 +/- 1.2 +/- 0.5, and B (B0 --> f0(980) K*0) = 2.6 +/- 0.6 +/- 0.9 ( rho+ K*0) = 0.52 +/- 0.10 +/- 0.04, f_L (B0 --> rho0 K*0) = 0.57 +/- 0.09 +/- 0.08, A_CP (B+ --> rho+ K*0) = -0.01 +/- 0.16 +/- 0.02, A_CP (B0 --> rho0 K*0) = 0.0…

Measurement of inclusive jet and dijet cross sections in proton-proton collisions at 7 TeV centre-of-mass energy with the ATLAS detector

Jet cross sections have been measured for the first time in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector. The measurement uses an integrated luminosity of 17 nb−1 recorded at the Large Hadron Collider. The anti-k t algorithm is used to identify jets, with two jet resolution parameters, R=0.4 and 0.6. The dominant uncertainty comes from the jet energy scale, which is determined to within 7% for central jets above 60 GeV transverse momentum. Inclusive single-jet differential cross sections are presented as functions of jet transverse momentum and rapidity. Dijet cross sections are presented as functions of dijet mass and the angular variable χ. The res…

Measurement ofD*±meson production in jets fromppcollisions ats=7  TeVwith the ATLAS detector

This paper reports a measurement of D*(+/-) meson production in jets from proton- proton collisions at a center- of- mass energy of root s = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb(-1) for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range vertical bar eta vertical bar D-0 pi(+), D-0 -> K-pi(+), and its charge conjugate. The production rate is found to be N(D*(+/-))/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*(+/-) mesons that carry a fraction z of the jet momentum in the range 0.3< z< 1. Monte Carlo predictions fail to describe the dat…

Measurement of theCPAsymmetry and Branching Fraction ofB0→ρ0K0

We present a measurement of the branching fraction and time-dependent CP asymmetry of B^0 to rho^0 K^0. The results are obtained from a data sample of 227 10^6 Y4S to BB_ decays collected with the BaBar detector at the PEP2 asymmetric-energy B Factory at SLAC. From a time-dependent maximum likelihood fit yielding 111+/-19 signal events we find B(B^0 to rho^0 K^0)=(4.9+/-0.8+/-0.9) 10^-6, where the first error is statistical and the second systematic. We report the measurement of the CP parameters S=0.20+/-0.52+/-0.24 and C=0.64+/-0.41+/-0.20.

Measurement ofCPobservables for the decaysB±→DCP0K*±

We present a study of the decay B^- → D^0_(CP)K^± and its charge conjugate, where D^0_CP) is reconstructed in CP-even, CP-odd, and non-CP flavor eigenstates, based on a sample of 232 x 10^6 Y(4S) → BB decays collected with the BABAR detector at the PEP-II e^+e^- storage ring. We measure the partial-rate charge asymmetries A_(CP±) and the ratios R_(CP±) of the B → D^0K decay branching fractions as measured in CP^± and non-CP D^0 decays: A_(CP±) 0:35 ± 0.13(stat) ± 0.04(syst), A_(CP-)= -0.06 ± 0.13(stat) ± 0.04(syst), R_(CP+) = 0.90 ± 0.12(stat) ± 0.049syst), and R_(CP-) = 0:86 ± 0.10(stat) ± 0.05(syst).

Measurement of the absolute branching fraction of D-0 -> K-pi(+)

We measure the absolute branching fraction for D0 --> K- pi+ using partial reconstruction of B0bar --> D^{*+} X \ell^{-} \bar{\nu}_{\ell} decays, in which only the charged lepton and the pion from the decay D^{*+} --> D0 pi^+ are used. Based on a data sample of 230 million B Bbar pairs collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, we obtain the absolute branching fractions of D0 --> K- pi+ = (4.007 \pm 0.037 \pm 0.072)%, where the first uncertainty is statistical and the second is systematic.

Search for high-mass resonances decaying to dilepton final states in pp collisions at √s = 7 TeV with the ATLAS detector

The ATLAS detector at the Large Hadron Collider is used to search for high-mass resonances decaying to an electron-positron pair or a muon-antimuon pair. The search is sensitive to heavy neutral Z′ gauge bosons, Randall-Sundrum gravitons, Z [superscript *] bosons, techni-mesons, Kaluza-Klein Z/γ bosons, and bosons predicted by Torsion models. Results are presented based on an analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.9 fb[superscript −1] in the e [superscript +] e [superscript −] channel and 5.0 fb[superscript −1] in the μ [superscript +] μ [superscript −] channel. A Z [superscript ′] boson with Standard Model-like couplings…

Measurement of theB+→pp¯K+branching fraction and study of the decay dynamics

With a sample of 232x10^6 Upsilon(4S) --> BBbar events collected with the BaBar detector, we study the decay B+ --> p pbar K+ excluding charmonium decays to ppbar. We measure a branching fraction Br(B+ --> p pbar K+)=(6.7+/-0.5+/-0.4)x10^{-6}. An enhancement at low ppbar mass is observed and the Dalitz plot asymmetry suggests dominance of the penguin amplitude in this B decay. We search for a pentaquark candidate Theta*++ decaying into pK+ in the mass range 1.43 to 2.00 GeV/c2 and set limits on Br(B+ --> Theta*++pbar)xBr(Theta*++ --> pK+) at the 10^{-7} level.

Branching fraction and charge asymmetry measurements in B→J/ψππ decays

The authors study the decays B{sup 0} {yields} J/{psi} {pi}{sup +}{pi}{sup -} and B{sup +} {yields} J/{psi} {pi}{sup +}{pi}{sup 0}, including intermediate resonances, using a sample of 382 million B{bar B} pairs recorded by the BABAR detector at the PEP-II e{sup +}e{sup -} B factory. They measure the branching fractions {Beta}(B{sup 0} {yields} J/{psi} {rho}{sup 0}) = (2.7 {+-} 0.3 {+-} 0.17) x 10{sup -5} and {Beta}(B{sup +} {yields} J/{psi} {rho}{sup +}) = (5.0 {+-} 0.7 {+-} 0.31) x 10{sup -5}. The authors also set the following upper limits at the 90% confidence level: {Beta}(B{sup 0} {yields} J/{psi} {pi}{sup +}{pi}{sup -} non-resonant) < 1.2 x 10{sup -5}, {Beta}(B{sup 0} {yields} J/{psi…

Measurement of the DecayB−→D*0e−ν¯e

Using 226 x 10(6) BB[overline] events recorded on the Upsilon(4S) resonance with the BABAR detector at the SLAC e(+)e(-) PEP-II storage rings, we reconstruct B(-) ---> D(*0)e(-)nu[overline](e) decays using the decay chain D(*0) --> D(0)pi(0) and D(0)-->K(-)pi(+). From the dependence of their differential rate on w, the dot product of the four velocities of B(-) and D(*0), and using the form factor description by Caprini et al. with the parameters F(1) and rhoA(1)(2), we obtain the results rhoA(1)(2) = 1.16+/-0.06+/-0.08, F(1)|V(cb)|=(35.9+/-0.6+/-1.4) x 10(-3), and B(B(-) --> D(*0)e(-)nu[overline](e))=(5.56+/-0.08+/-0.41)%.

Measurement of branching fractions andCPand isospin asymmetries forB→K*γ

We present a preliminary analysis of the decays B{sup 0} {yields} K*{sup 0}{gamma} and B{sup +} {yields} K*{sup +}{gamma} using a sample of 383 million B{bar B} events collected with the BABAR detector at the PEP-II asymmetric energy B factory. We measure the branching fractions {Beta}(B{sup 0} {yields} K*{sup 0}{gamma}) = (4.58 {+-} 0.10 {+-} 0.16) x 10{sup -5} and {Beta}(B{sup +} {yields} K*{sup +}{gamma}) = (4.73 {+-} 0.15 {+-} 0.17) x 10{sup -5}. We measure the direct CP asymmetry to be -0.043 < {Alpha}(B {yields} K*{gamma}) < 0.025 and the isospin asymmetry to be -0.021 < {Delta}{sub 0-} < 0.079, where the limits are determined at the 90% confidence interval and include both the statis…

Observation ofB+→ρ+K0and measurement of its branching fraction and charge asymmetry

We present the first observation of the decay B+→ρ+K0, using a data sample of 348fb-1 collected at the Υ(4S) resonance with the BABAR detector. The branching fraction and charge asymmetry are measured to be (8.0-1.3+1.4±0.6)×10-6 and (-12.2±16.6±2.0)%, respectively, where the first uncertainty is statistical and the second is systematic. The charge asymmetry is defined by Ach=(ΓB - ΓB+)/(ΓB-+ΓB+) with ΓB± the B± decay rate. The significance of the observed branching fraction, including systematic uncertainties, is 7.9 standard deviations. © 2007 The American Physical Society.

Measurement of time-dependentCP-violating asymmetries and constraints onsin(2β+γ)with partial reconstruction ofB→D*∓π±decays

We present a measurement of the time-dependent CP-violating asymmetries in decays of neutral B mesons to the final states D*-+ pi+-, using approximately 232 million BBbar events recorded by the BABAR experiment at the PEP2 e+e- storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum pi+- from the B decay and the low-momentum pi-+ from the D*-+ decay are used. % We measure the parameters related to 2beta+gamma to be a_D*pi=-0.034 +- 0.014 +- 0.009 and c_l_D*pi = -0.019 +- 0.022 +- 0.013. With some theoretical assumptions, we interpret our results in term of the lower limits |\sin(2beta+gamma)|> 0.62 (0.35) at 68% (90%…

Search for Supersymmetry inppCollisions ats=7  TeVin Events with Two Photons and Missing Transverse Energy

A search for supersymmetry in the context of general gauge-mediated breaking with the lightest neutralino as the next-to-lightest supersymmetric particle and the gravitino as the lightest is presented. The data sample corresponds to an integrated luminosity of 36 pb(-1) recorded by the CMS experiment at the LHC. The search is performed by using events containing two or more isolated photons, at least one hadronic jet, and significant missing transverse energy. No excess of events at high missing transverse energy is observed. Upper limits on the signal cross section for general gauge-mediated supersymmetry between 0.3 and 1.1 pb at the 95% confidence level are determined for a range of squa…

Search forD0−D¯0Mixing and a Measurement of the Doubly Cabibbo-Suppressed Decay Rate inD0→KπDecays

The authors present a search for D{sup 0}-{bar D}{sup 0} mixing using regions of phase space in which the rate of doubly Cabibbo-suppressed decays D{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0} relative to Cabibbo-favored decays D{sup 0} {yields} K{sup -} {pi}{sup +}{pi}{sup 0} is reduced. They analyze 230.4 fb{sup -1} of data collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. They present results with and without the assumption of CP conservation. Assuming CP conservation, they measure the time-integrated mixing rate R{sub M} = (0.023{sub -0.014}{sup +0.018}(stat.) {+-} 0.004(syst.))%, and R{sub M} < 0.054% at the 95% confidence level. They find that the d…

Study of thee+e−→π+π−π0process using initial state radiation withBABAR

The process e+e- --> pi+ pi- pi0 gamma has been studied at a center-of-mass energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum we have obtained the products of branching fractions for the omega and phi mesons, B(omega --> e+e-)B(omega --> 3pi)=(6.70 +/- 0.06 +/- 0.27)10-5 and B(phi --> e+e-)B(phi --> 3pi)=(4.30 +/- 0.08 +/- 0.21)10-5, and evaluated the e+e- --> pi+ pi- pi0 cross section for the e+e- center-of-mass energy range 1.05 to 3.00 GeV. About 900 e+e- --> J/psi gamma --> pi+ pi- pi0 gamma events have been selected and the branching fraction B(J/psi --> pi+ pi- pi0)=(2.18 +/- 0.19…

Dalitz plot analysis of the decayB0(B¯0)→K±π∓π0

The authors report a Dalitz-plot analysis of the charmless hadronic decays of neutral B mesons to K{sup {+-}}{pi}{sup {-+}}{pi}{sup 0}. With a sample of (231.8 {+-} 2.6) x 10{sup 6}{Upsilon}(4S) {yields} B{bar B} decays collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, they measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for B{sup 0} and {bar B}{sup 0} decays and determine the corresponding CP-averaged branching fractions and charge asymmetries. The inclusive branching fraction and CP-violating charge asymmetry are measured to be {Beta}(B{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0}) = (35.7{sub -1.5}{sup +2.6} {+-…

Search for anomalous production of prompt like-sign muon pairs and constraints on physics beyond the Standard Model with the ATLAS detector

An inclusive search for anomalous production of two prompt, isolated muons with the same electric charge is presented. The search is performed in a data sample corresponding to 1.6  fb−1 of integrated luminosity collected in 2011 at √s=7  TeV with the ATLAS detector at the LHC. Muon pairs are selected by requiring two isolated muons of the same electric charge with pT>20  GeV and |η|<2.5. Minimal requirements are placed on the rest of the event activity. The distribution of the invariant mass of the muon pair m(μμ) is found to agree well with the background expectation. Upper limits on the cross section for anomalous production of two muons with the same electric charge are placed as a func…

Observation of a Centrality-Dependent Dijet Asymmetry in Lead-Lead Collisions atsNN=2.76  TeVwith the ATLAS Detector at the LHC

By using the ATLAS detector, observations have been made of a centrality-dependent dijet asymmetry in the collisions of lead ions at the Large Hadron Collider. In a sample of lead-lead events with a per-nucleon center of mass energy of 2.76 TeV, selected with a minimum bias trigger, jets are reconstructed in fine-grained, longitudinally segmented electromagnetic and hadronic calorimeters. The transverse energies of dijets in opposite hemispheres are observed to become systematically more unbalanced with increasing event centrality leading to a large number of events which contain highly asymmetric dijets. This is the first observation of an enhancement of events with such large dijet asymme…

Precise Measurement of thee+e−→π+π−(γ)Cross Section with the Initial State Radiation Method atBABAR

A precise measurement of the cross section for the process e^+e^- → K^+K^-(γ) from threshold to an energy of 5 GeV is obtained with the initial-state radiation (ISR) method using 232  fb^(-1) of data collected with the BABAR detector at e^+e^- center-of-mass energies near 10.6 GeV. The measurement uses the effective ISR luminosity determined from the e^+e^- → μ^+μ^-(γ)γ_(ISR) process with the same data set. The corresponding lowest-order contribution to the hadronic vacuum polarization term in the muon magnetic anomaly is found to be a_μ^(KK,LO)=(22.93 ± 0.18_(stat) ± 0.22_(syst))×10^(-10). The charged kaon form factor is extracted and compared to previous results. Its magnitude at large en…

Measurements of time-dependentCPasymmetries inB0→D(*)+D(*)−decays

We present new measurements of time-dependent CP asymmetries for B{sup 0} {yields} D{sup (*)+}d{sup (*)-} decays using (467 {+-} 5) x 10{sup 6} B{bar B} pairs collected with the BABAR detector located at the PEP-II B Factory at the Stanford Linear Accelerator Center. We determine the CP-odd fraction of the B{sup 0} {yields} D*{sup +}D*{sup -} decays to be R{perpendicular} = 0.158 {+-} 0.028 {+-} 0.006 and find CP asymmetry parameters for the CP-even component of the decay S{sub +} = -0.76 {+-} 0.16 {+-} 0.04 and C{sub +} = 0.00 {+-} 0.12 {+-} 0.02. We measure S = -0.63{+-}0.36{+-}0.05 and C = -0.07{+-}0.23{+-}0.03 for B{sup 0} {yields} D{sup +}D{sup -}, S = -0.62{+-}0.21{+-}0.03 and C = 0.0…

Search for Invisible Decays of theΥ(1S)

We search for invisible decays of the Upsilon(1S) meson using a sample of 91.4 x 10(6) Upsilon(3S) mesons collected at the BABAR/PEP-II B factory. We select events containing the decay Upsilon(3S) --> pi(+)pi(-)Upsilon(1S) and search for evidence of an undetectable Upsilon(1S) decay recoiling against the dipion system. We set an upper limit on the branching fraction B(Upsilon(1S) --> invisible) < 3.0 x 10(-4) at the 90% confidence level.

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of √s = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of Ks and Λ particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncert…

Measurement of the Branching Fractions ofB¯→D**ℓ−ν¯ℓDecays in Events Tagged by a Fully ReconstructedBMeson

We report a measurement of the branching fractions of D**- decays based on 417 fb-1 of data collected at the (4S) resonance with the BABAR detector at the PEP-II e+e- storage rings. Events are selected by fully reconstructing one of the B mesons in a hadronic decay mode. A fit to the invariant mass differences m(D(*))-m(D(*)) is performed to extract the signal yields of the different D** states. We observe the D**- decay modes corresponding to the four D** states predicted by heavy quark symmetry with a significance greater than 5 standard deviations including systematic uncertainties.

Measurements of the semileptonic decaysB¯→Dℓν¯andB¯→D*ℓν¯using a global fit toDXℓν¯final states

Semileptonic (B) over bar decays to DXl (nu) over bar (l = e or mu) are selected by reconstructing D(0)l and D(+)l combinations from a sample of 230 x 10(6) Y(4S) --> B (B) over bar decays recorded with the BABAR detector at the PEP-II e(+)e(-) collider at SLAC. A global fit to these samples in a three-dimensional space of kinematic variables is used to determine the branching fractions B(B- --> D(0)l (nu) over bar = (2.34 +/- 0.03 +/- 0.13)% and B(B- --> D*(0)l (nu) over bar) = (5.40 +/- 0.02 +/- 0.21)% where the errors are statistical and systematic, respectively. The fit also determines form-factor parameters in a parametrization based on heavy quark effective theory, resulting in rho(2)…

Determinations of|Vub|from Inclusive SemileptonicBDecays with Reduced Model Dependence

We report two novel determinations of |V{sub ub}| with reduced model dependence, based on measurements of the mass distribution of the hadronic system in semileptonic B decays. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson from {Upsilon}(4S) {yields} (B{bar B}) events. In one approach, we combine the inclusive {bar B} {yields} X{sub u}{ell}{bar {nu}} rate with a measurement of the inclusive B {yields} X{sub s}{gamma} photon energy spectrum. We obtain |V{sub ub}| = (4.43 {+-} 0.38{sub stat} {+-} 0.25{sub syst} {+-} 0.29{sub theo}) x 10{sup -3}. In another approach we measure the total {bar B} {yields}…

Study ofB→πℓνandB→ρℓνdecays and determination of|Vub|

We present an analysis of exclusive charmless semileptonic B-meson decays based on 83x10{sup 6} BB pairs recorded with the BABAR detector at the {upsilon}(4S) resonance. Using isospin symmetry, we measure branching fractions B(B{sup 0}{yields}{pi}{sup -}l{sup +}{nu})=(1.38{+-}0.10{+-}0.16{+-}0.08)x10{sup -4} and B(B{sup 0}{yields}{rho}{sup -}l{sup +}{nu})=(2.14{+-}0.21{+-}0.48{+-}0.28)x10{sup -4}, where the errors are statistical, experimental systematic, and due to form-factor shape uncertainties. We compare the measured distribution in q{sup 2}, the momentum-transfer squared, with theoretical predictions for the form factors from lattice QCD and light-cone sum rules, and extract the Cabib…

Search for the rare decaysB0→Ds(*)+a0(2)−

We have searched for the decays B{sup 0}{yields}D{sub s}{sup +}a{sub 0}{sup -}, B{sup 0}{yields}D{sub s}*{sup +}a{sub 0}{sup -}, B{sup 0}{yields}D{sub s}{sup +}a{sub 2}{sup -} and B{sup 0}{yields}D{sub s}*{sup +}a{sub 2}{sup -} in a sample of about 230x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We find no evidence for these decays and set upper limits at 90% C.L. on the branching fractions: B(B{sup 0}{yields}D{sub s}{sup +}a{sub 0}{sup -})<1.9x10{sup -5}, B(B{sup 0}{yields}D{sub s}*{sup +}a{sub 0}{sup -})<3.6x10{sup -5}, B(B{sup 0}{yields}D{sub s}{sup +}a{sub 2}{sup -})<1.9x10{sup -4}, and B(B{sup 0}{yields}D…

The ATLAS Inner Detector commissioning and calibration

The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and insitu calibrations are described. Tracking performance has been measured with 7.6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energ…

Measurements of the branching fraction and time-dependentCPasymmetries ofB0→J/ψπ0decays

We present measurements of the branching fraction and time-dependent CP asymmetries in B{sup 0} {yields} J/{psi}{pi}{sup 0} decays based on (231.8 {+-} 2.6) x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. We obtain a branching fraction {Beta}(B{sup 0} {yields} J/{psi}{pi}{sup 0}) = (1.94 {+-} 0.22 (stat) {+-} 0.17 (syst)) x 10{sup -5}. We also measure the CP asymmetry parameters C = -0.21 {+-} 0.26 (stat) {+-} 0.06 (syst) and S = -0.68 {+-} 0.30 (stat) {+-} 0.04 (syst).

Evidence for the decayB±→K*±π0

We have measured the process B±→ (K*±→K±π0)π0 with 232×106 Υ(4S) →BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. From a signal yield of 89±26 events we obtain the branching fraction B(B±→K*±π0)=[6. 9±2.0(stat)±1.3(syst)]×10-6 with a statistical significance of 3.6 standard deviations including systematic uncertainties, and a charge asymmetry of 0.04±0.29(stat)±0.05(syst). © 2005 The American Physical Society.

Observation of a NewDsMeson Decaying toDKat a Mass of2.86  GeV/c2

We observe a new D_s meson with mass (2856.6 +/- 1.5_{stat.} +/- 5.0_{syst.}) MeV/c^2 and width (48 +/- 7_{stat.} +/- 10_{syst.}) MeV decaying into D^0 K^+ and D^+K^0_S. In the same mass distributions we also observe a broad structure with mass (2688 +/- 4_{stat.} +/- 3_{syst.}) MeV/c^2 and width (112 +/- 7_{stat.} +/- 36_{syst.}) MeV. To obtain this result we use 240 fb^-1 of data recorded by the BaBar detector at the PEP-II asymmetric-energy e^+e^- storage rings at the Stanford Linear Accelerator Center running at center-of-mass energies near 10.6 GeV.

Search for massive long-lived highly ionising particles with the ATLAS detector at the LHC

A search is made for massive highly ionising particles with lifetimes in excess of 100 ns, with the ATLAS experiment at the Large Hadron Collider, using 3.1 pb-1 of pp collision data taken at √s = 7TeV. The signature of energy loss in the ATLAS inner detector and electromagnetic calorimeter is used. No such particles are found and limits on the production cross section for electric charges 6e ≤ |q| ≤ 17e and masses 200 GeV ≤ m ≤ 1000 GeV are set in the range 1–12 pb for different hypotheses on the production mechanism.

Search forB±→[K∓π±]DK±and Upper Limit on theb→uAmplitude inB±→DK±

We search for B±→[K∓π±]DK± decays, where [K∓π±]D indicates that the K∓π± pair originates from the decay of a D0 or D 0. Results are based on 120×106 Υ(4S)→BB decays collected with the BABAR detector at SLAC. We set an upper limit on the ratio RKπ≡ [Γ(B+→[K-π+]DK+)+Γ(B-→[K+π-]DK-)]/[Γ(B+→[K+π-]DK+)+Γ(B-→[K-π+]DK-)]<0.026 (90%   C.L.). This constrains the amplitude ratio rB≡ |A(B-→D 0K-)/A(B-→D0K-)|<0.22 (90% C.L.), consistent with expectations. The small value of rB favored by our analysis suggests that the determination of the Cabibbo-Kobayashi-Maskawa phase γ from B→DK will be difficult.

Search for Down-Type Fourth Generation Quarks with the ATLAS Detector in Events with One Lepton and Hadronically Decaying W Bosons

This Letter presents a search for pair production of heavy down-type quarks decaying via b′→Wt in the lepton+jets channel, as b′¯b′→W−tW+¯t→b¯bW+W−W+W−→l±νb¯bq¯qq¯qq¯q. In addition to requiring exactly one lepton, large missing transverse momentum, and at least six jets, the invariant mass of nearby jet pairs is used to identify high transverse momentum W bosons. In data corresponding to an integrated luminosity of 1.04  fb−1 from pp collisions at √s=7  TeV recorded with the ATLAS detector, a heavy down-type quark with mass less than 480 GeV can be excluded at the 95% confidence level.

Observation of theχc2(2P)meson in the reactionγγ→DD¯atBABAR

A search for the Z(3930) resonance in gamma gamma production of the DDbar system has been performed using a data sample corresponding to an integrated luminosity of 384 fb^-1 recorded by the BABAR experiment at the PEP-II asymmetric-energy electron-positron collider. The DDbar invariant mass distribution shows clear evidence of the Z(3930) state with a significance of 5.8 sigma. We determine mass and width values of (3926.7 +- 2.7 +- 1.1) MeV/c^2 and (21.3 +- 6.8 +- 3.6) MeV, respectively. A decay angular analysis provides evidence that the Z(3930) is a tensor state with positive parity and C-parity (J^PC = 2^++); therefore we identify the Z(3930) state as the chi_c2(2P) meson. The value of…

Study of jet shapes in inclusive jet production inppcollisions ats=7  TeVusing the ATLAS detector

Jet shapes have been measured in inclusive jet production in proton-proton collisions at root s = 7 TeV using 3 pb(-1) of data recorded by the ATLAS experiment at the LHC. Jets are reconstructed using the anti-k(t) algorithm with transverse momentum 30 GeV < p(T) < 600 GeV and rapidity in the region vertical bar y vertical bar < 2.8. The data are corrected for detector effects and compared to several leading-order QCD matrix elements plus parton shower Monte Carlo predictions, including different sets of parameters tuned to model fragmentation processes and underlying event contributions in the final state. The measured jets become narrower with increasing jet transverse momentum and the je…

Measurements of branching fractions forB+→ρ+γ,B0→ρ0γ, andB0→ωγ

We present branching fraction measurements for the radiative decays B{sup +}{yields}{rho}{sup +}{gamma}, B{sup 0}{yields}{rho}{sup 0}{gamma}, and B{sup 0}{yields}{omega}{gamma}. The analysis is based on a data sample of 465x10{sup 6} BB events collected with the BABAR detector at the PEP-II asymmetric-energy B Factory located at the Stanford Linear Accelerator Center. We find B(B{sup +}{yields}{rho}{sup +}{gamma})=(1.20{sub -0.37}{sup +0.42}{+-}0.20)x10{sup -6}, B(B{sup 0}{yields}{rho}{sup 0}{gamma})=(0.97{sub -0.22}{sup +0.24}{+-}0.06)x10{sup -6}, and a 90% C.L. upper limit B(B{sup 0}{yields}{omega}{gamma})<0.9x10{sup -6}, where the first error is statistical and the second is systematic. …

Evidence for ChargedBMeson Decays toa1±(1260)π0anda10(1260)π±

We present measurements of the branching fractions for the decays B±→a1±(1260)π0 and B±→a10(1260)π± from a data sample of 232×106 BB pairs produced in e+e- annihilation through the Υ(4S) resonance. We measure the branching fraction B(B±→a1±(1260)π0)×B(a1±(1260) →π-π+π±)=(13.2±2.7±2.1)×10-6 with a significance of 4.2σ, and the branching fraction B(B±→ a10(1260)π±)×B(a10(1260)→π-π+π0)=(20.4±4. 7±3.4)×10-6 with a significance of 3.8σ, where the first error quoted is statistical and the second is systematic. © 2007 The American Physical Society.

Search for decays of stopped, long-lived particles from 7 TeV pp collisions with the ATLAS detector

New metastable massive particles with electric and colour charge are features of many theories beyond the Standard Model. A search is performed for long-lived gluino-based R-hadrons with the ATLAS detector at the LHC using a data sample corresponding to an integrated luminosity of 31 pb[superscript −1]. We search for evidence of particles that have come to rest in the ATLAS detector and decay at some later time during the periods in the LHC bunch structure without proton–proton collisions. No significant deviations from the expected backgrounds are observed, and a cross-section limit is set. It can be interpreted as excluding gluino-based R-hadrons with masses less than 341 GeV at the 95 % …

Measurement of theB¯0→D*+ℓ−ν¯ℓdecay rate and|Vcb|

We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ based on a sample of about 53,700 \mbox{$\Bzb \rightarrow D^{*+} \ell^- \bar{\nu}_{\ell}$} decays observed by the \babar\ detector. We obtain the branching fraction averaged over $\ell = e,\mu$, ${\cal B}(\Bzb \rightarrow D^{*+} \ell^- \bar{\nu}_{\ell}) = (4.90 \pm 0.07\mathrm{(stat.)}^{+0.36}_{-0.35}\mathrm{(syst.)})\%$. We measure the differential decay rate as a function of $w$, the relativistic boost $\gamma$ of the $D^{*+}$ in the ${\Bzb}$ rest frame. By extrapolating $d\Gamma/dw$ to the kinematic limit $w \rightarrow 1$, we extract the product of $|V_{cb}|$ and the axial form factor ${\cal A}_1(w=1)$. …

Search for Scalar Bottom Quark Pair Production with the ATLAS Detector inppCollisions ats=7  TeV

The results of a search for pair production of the scalar partners of bottom quarks in 2: 05 fb(-1) of pp collisions at root s = 7 TeV using the ATLAS experiment are reported. Scalar bottom quarks ...

Measurement of inclusive jet and dijet production inppcollisions ats=7  TeVusing the ATLAS detector

Inclusive jet and dijet cross sections have been measured in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector at the Large Hadron Collider. The cross sections were measured using jets clustered with the anti-kT algorithm with parameters R=0.4 and R=0.6. These measurements are based on the 2010 data sample, consisting of a total integrated luminosity of 37 inverse picobarns. Inclusive jet double-differential cross sections are presented as a function of jet transverse momentum, in bins of jet rapidity. Dijet double-differential cross sections are studied as a function of the dijet invariant mass, in bins of half the rapidity separation of the two leading …

Measurement of $ZZ$ production in $pp$ collisions at $\sqrt{s}=7$ TeV and limits on anomalous $ZZZ$ and $ZZ\gamma$ couplings with the ATLAS detector

Journal of High Energy Physics 2013.3 (2013): 128 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)

Search for events with large missing transverse momentum, jets, and at least two tau leptons in 7 TeV proton–proton collision data with the ATLAS detector

A search for events with large missing transverse momentum, jets, and at least two tau leptons has been performed using 2 fb[superscript −1] of proton–proton collision data at √s = 7 TeV recorded with the ATLAS detector at the Large Hadron Collider. No excess above the Standard Model background expectation is observed and a 95% CL upper limit on the visible cross section for new phenomena is set, where the visible cross section is defined by the product of cross section, branching fraction, detector acceptance and event selection efficiency. A 95% CL lower limit of 32 TeV is set on the gauge-mediated supersymmetry breaking (GMSB) scale Λ independent of tan β. These limits provide the most s…

Inclusive search for same-sign dilepton signatures in pp collisions at $ sqrt {s} = 7 $ TeV with the ATLAS detector

An inclusive search is presented for new physics in events with two isolated leptons (e or mu) having the same electric charge. The data are selected from events collected from p p collisions at root s = 7 TeV by the ATLAS detector and correspond to an integrated luminosity of 34 pb(-1). The spectra in dilepton invariant mass, missing transverse momentum and jet multiplicity are presented and compared to Standard Model predictions. In this event sample, no evidence is found for contributions beyond those of the Standard Model. Limits are set on the cross-section in a fiducial region for new sources of same-sign high-mass dilepton events in the ee, e mu and mu mu channels. Four models predic…

Time-dependent Dalitz plot analysis ofB0→D∓K0π±decays

We present for the first time a measurement of the weak phase 2 beta+gamma obtained from a time-dependent Dalitz plot analysis of B-0 ->(DK0)-K--/+pi(+/-) decays. Using a sample of approximately 347x10(6) B (B) over bar pairs collected by the BABAR detector at the PEP-II asymmetric-energy storage rings and assuming the ratio r of the b -> u and b -> c decay amplitudes to be 0.3, we obtain 2 beta+gamma=(83 +/- 53 +/- 20)degrees and the equivalent solution at +180 degrees. The magnitudes and phases for the resonances associated with the b -> c transitions are also extracted from the fit.

Search for the rare decayB¯0→D*0γ

SLAC for its support and the kind hospitality extended to them. This work is supported by the US Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), Institute of High Energy Physics (China), the Commissariat `a l’Energie Atomique and Institut National de Physique Nucl´eaire et de Physique des Particules (France), the Bundesministerium fu¨r Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Foundation for Fundamental Research on Matter (The Netherlands), the Research Council of Norway, the Ministry of Science and Technology of the Russian Federation, and …

Search for Pair Production of a Heavy Up-Type Quark Decaying to aWBoson and abQuark in thelepton+jetsChannel with the ATLAS Detector

A search is presented for production of a heavy up-type quark (t') together with its antiparticle, assuming subsequent decay to a W boson and a b quark, t'(t) over bar' -> W(+)bW(-)(b) over bar. The search is based on 1.04 fb(-1) of proton-proton collisions at root s = 7 TeV collected by the ATLAS detector at the CERN Large Hadron Collider. Data are analyzed in the lepton + jets final state, characterized by a high transverse momentum isolated electron or muon, high missing transverse momentum, and at least three jets. No significant excess of events above the background expectation is observed. A 95% C.L. lower limit of 404 GeV is set for the mass of the t' quark.

Search forB0→ϕ(K+π−)decays with largeK+π−invariant mass

Motivated by the polarization anomaly in the B→ (1020)K*(892) decay, we extend our search for other K* final states in the decay B0→ (1020)K*0 with the K*0→K+π- invariant mass above 1.6 GeV. The final states considered include the K*(1680)0, K3*(1780)0, K4*(2045)0, and a Kπ spin-zero nonresonant component. We also search for B0→ D0 decay with the same final state. The analysis is based on a sample of about 384×106 BB pairs recorded with the BABAR detector. We place upper limits on the branching fractions B(B0→ K*(1680)0)<3.5×10-6, B(B0→ K3*(1780)0) <2.7×10-6, B(B0→ K4*(2045)0)<15.3×10-6, and B(B0→ D0)<11.7×10-6 at 90% C.L. The nonresonant contribution is consistent with the measurements in …

Search for the Higgs Boson in theH→WW→lνjjDecay Channel inppCollisions ats=7  TeVwith the ATLAS Detector

A search for a Higgs boson has been performed in the H -> WW -> l nu jj channel in 1.04 fb(-1) of pp collision data at root s = 7 TeV recorded with the ATLAS detector at the Large Hadron Collider. No significant excess of events is observed over the expected background and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range 240 GeV WW production is 3.1 pb, or 2.7 times the standard model prediction.

Search forCPviolation usingT-odd correlations inD+→K+KS0π+π−andDs+→K+KS0π+π−decays

We search for CP violation in a sample of 20,000 Cabibbo-suppressed decays, $D^+\rightarrow K^+K^0_S\pi^+\pi^-$, and 30,000 Cabibbo-favored decays, $D_s^+\rightarrow K^+K^0_S\pi^+\pi^-$. We use 520 $fb^{-1}$ of data recorded by the BaBar detector at the PEP-II asymmetric-energy $e^+e^-$ collider operating at center of mass energies near 10.6 $GeV$. We search for CP violation in the difference between the $T$-odd asymmetries obtained using triple product correlations of the $D^+$ ($D_s^+$) and $D^-$ ($D_s^-$) decays, respectively. The $T$ violation parameter values obtained are $\mathcal{A}_T(D^+) = (-12.0 \pm 10.0_{stat} \pm 4.6_{syst})\times 10^{-3}$ and $\mathcal{A}_T(D_s^+) = (-13.6 \pm …

Ks0andΛproduction inppinteractions ats=0.9and 7 TeV measured with the ATLAS detector at the LHC

The production of K(S)(0) and Lambda hadrons is studied in pp collision data at root s = 0.9 and 7 TeV collected with the ATLAS detector at the LHC using a minimum-bias trigger. The observed distributions of transverse momentum, rapidity, and multiplicity are corrected to hadron level in a model-independent way within well-defined phase-space regions. The distribution of the production ratio of (Lambda) over bar to Lambda baryons is also measured. The results are compared with various Monte Carlo simulation models. Although most of these models agree with data to within 15% in the K(S)(0) distributions, substantial disagreements are found in the Lambda distributions of transverse momentum.

Search for the Standard Model Higgs boson in the decay channel H→ZZ(⁎)→4ℓ with 4.8 fb−1 of pp collision data at s=7 TeV with ATLAS

This Letter presents a search for the Standard Model Higgs boson in the decay channel H -> ZZ((*)) -> l(+)l(-)l(-)+l(')-, where l,l' = e or mu, using proton-proton collisions at root s = 7 TeV recorded with the ATLAS detector and corresponding to an integrated luminosity of 4.8 fb(-1). The four-lepton invariant mass distribution is compared with Standard Model background expectations to derive upper limits on the cross section of a Standard Model Higgs boson with a mass between 110 GeV and 600 GeV. The mass ranges 134-156 GeV, 182-233 GeV, 256-265 GeV and 268-415 GeV are excluded at the 95% confidence level. The largest upward deviations from the background-only hypothesis are observed for …

Measurement of the distributions of event-by-event flow harmonics in lead-lead collisions at = 2.76 TeV with the ATLAS detector at the LHC

We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWF and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; EPLANET, ERC and NSRF, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG and AvH Foundation, Germany; GSRT and NSRF, Greece; ISF, MINERVA, GIF, DIP and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Norway; MNiSW, Poland; GRICES and FCT, Portu…

Measurement of theηandη′transition form factors atq2=112  GeV2

We report a study of the processes e^+e^-→ηγ and e^+e^-→η′γ at a center-of-mass energy of 10.58 GeV, using a 232  fb^(-1) data sample collected with the BABAR detector at the PEP-II collider at SLAC. We observe 20_(-5)^(+6)ηγ and 50_(-7)^(+8)η′γ events over small backgrounds, and measure the cross sections σ(e^+e^-→ηγ)=4.5_(-1.1)^(+1.2)±0.3  fb and σ(e^+e^-→η′γ)=5.4±0.8±0.3  fb. The corresponding transition form factors at q^2=112  GeV^2 are q^2|F_η(q^2)|=0.229±0.030±0.008  GeV, and q^2|F_η′(q^2)|=0.251±0.019±0.008  GeV, respectively.

Search for high mass dilepton resonances in pp collisions at s=7 TeV with the ATLAS experiment

This Letter presents a search for high mass e(+)e(-) or mu(+)mu(-) resonances in pp collisions at root s = 7 TeV at the LHC. The data were recorded by the ATLAS experiment during 2010 and correspon ...

Thee+e−→3(π+π−),2(π+π−π0)andK+K−2(π+π−)cross sections at center-of-mass energies from production threshold to 4.5 GeV measured with initial-state radiation

We study the processes e^+e^- → 3(π^+π^-)γ, 2(π^+π^-π^0)γ and K^+K^-2(π^+π^-)γ, with the photon radiated from the initial state. About 20 000, 33 000 and 4000 fully reconstructed events, respectively, have been selected from 232  fb^(-1) of BABAR data. The invariant mass of the hadronic final state defines the effective e^+e^- center-of-mass energy, so that these data can be compared with the corresponding direct e^+e^- measurements. From the 3(π^+π^-), 2(π^+π^-π^0) and K^+K^-2(π^+π^-) mass spectra, the cross sections for the processes e^+e^- → 3(π^+π^-), e^+e^- → 2(π^+π^-π^0) and e^+e^- → K^+K^-2(π^+π^-) are measured for center-of-mass energies from production threshold to 4.5 GeV. The unc…

Measurement of Wγ and Zγ production in proton-proton collisions at √s =7 TeV with the ATLAS detector

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM

The BaBar detector: Upgrades, operation and performance

The BABAR detector operated successfully at the PEP-Il asymmetric e(+) e(-) collider at the SLAC National Accelerator Laboratory from 1999 to 2008. This report covers upgrades, operation, and performance of the collider and the detector systems, as well as the trigger, online and offline computing, and aspects of event reconstruction since the beginning of data taking.

Measurement of Branching Fractions and Resonance Contributions forB0→D¯0K+π−and Search forB0→D0K+π−Decays

Using 226×10^6 Υ(4S)→BB events collected with the BABAR detector at the PEP-II e^+e^- storage ring at the Stanford Linear Accelerator Center, we measure the branching fraction for B^0→D^0K^+π^-, excluding B^0→D^(*-)K^+, to be B(B^0→D^0K^+π^-)=(88±15±9)×10^(-6). We observe B^0→D^0K^*(892)^0 and B^0→D_2^*(2460)^-K^+ contributions. The ratio of branching fractions B(B^0→D^(*-)K^+)/B(B^0→D^(*-)π^+)=(7.76±0.34±0.29)% is measured separately. The branching fraction for the suppressed mode B^0→D^0K^+π^- is B(B^0→D^0K^+π^-)<19×10^(-6) at the 90% confidence level.

Measurement of the Branching Fractions of ExclusiveB¯→D(*)(π)l−ν¯lDecays in Events with a Fully ReconstructedBMeson

We report a measurement of the branching fractions for _B-->D(*)(pi)l- _nu(l) decays based on 341.1 fb(-1) of data collected at the Upsilon(4S) resonance with the BABAR detector at the SLAC PEP-II e+ e- storage rings. Events are tagged by fully reconstructing one of the B mesons in a hadronic decay mode. We obtain B(B- -->D(0)l-_nu(l)=(2.33+/-0.09(stat)+/-0.09(syst)%, B(B- -->D(*0)l-_nu(l)=(5.83+/-0.15(stat) +/-0.30(syst) %, B(_B(0)-->D+l-_nu(l)=(2.21+/-0.11(stat) +/-0.12(syst)%, B(_B(0)-->D(*)l-_nu(l)=(5.49+/-0.16(stat)+/-0.25(syst)%, B(B- -->D+pi-l-_nu(l)=(0.42+/-0.06(stat)+/-0.03(syst)%, B(B- -->D(*)+pi-l-_nu(l)=(0.59+/-0.05(stat)+/-0.04(syst)%, B(_B(0)-->D(0)pi+l-_nu(l)=(0.43+/-0.08(sta…

Search for quark contact interactions in dijet angular distributions in pp collisions at s=7 TeV measured with the ATLAS detector

Dijet angular distributions from the first LHC pp collisions at center-of-mass energy sqrt(s) = 7 TeV have been measured with the ATLAS detector. The dataset used for this analysis represents an integrated luminosity of 3.1 pb-1. Dijet $\chi$ distributions and centrality ratios have been measured up to dijet masses of 2.8 TeV, and found to be in good agreement with Standard Model predictions. Analysis of the $\chi$ distributions excludes quark contact interactions with a compositeness scale $\Lambda$ below 3.4 TeV, at 95% confidence level, significantly exceeding previous limits.

Observation of inclusiveD*±production in the decay ofΥ(1S)

We present a study of the inclusive D*(+/-) production in the decay of Y(1S) using (98.6 +/- 0.9) X 10(6) Y(2S) mesons collected with the BABAR detector at the Y(2S) resonance. Using the decay chain Y(2S) -> pi(+)pi Y-(1S), Y(1S) -> D*X-+/-, where X is unobserved, we measure the branching fraction B[Y(1S) -> D*X-+/-] = (2.52 +/- 0.13(stat) +/- 0.15(syst)% and the D*(+/-) momentum distribution in the rest frame of the Y(1S). We find evidence for an excess of D*+/- production over the expected rate from the virtual photon annihilation process Y(1S) -> gamma* -> c (c) over bar -> D*X-+/-.

Evidence for the spin-0 nature of the Higgs boson using ATLAS data

We acknowledge the support of ANPCyT, Argentina; YerPhl, Armenia; ARC, Australia; BMWF and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; EPLANET, ERC and NSRF, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG and AvH Foundation, Germany; GSRT and NSRF, Greece; ISF, MINERVA, GIF, DIP and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Norway; MNiSW, Poland; GRICES and FCT, Portu…

Measurement of dijet production with a veto on additional central jet activity in pp collisions at sqrt(s)=7 TeV using the ATLAS detector

A measurement of jet activity in the rapidity interval bounded by a dijet system is presented. Events are vetoed if a jet with transverse momentum greater than 20 GeV is found between the two boundary jets. The fraction of dijet events that survive the jet veto is presented for boundary jets that are separated by up to six units of rapidity and with mean transverse momentum 50 < p¯T < 500 GeV. The mean multiplicity of jets above the veto scale in the rapidity interval bounded by the dijet system is also presented as an alternative method for quantifying perturbative QCD emission. The data are compared to a next-to-leading order plus parton shower prediction from the powheg-box, an all-order…

Measurements ofCP-Violating Asymmetries inB0→Ks0π0Decays

The authors present measurements of CP-violating asymmetries in the decay B{sup 0} {yields} a{sub 1}{sup {+-}}(1260){pi}{sup {-+}} with a{sub 1}{sup {+-}}(1260) {yields} {pi}{sup {-+}}{pi}{sup {+-}}{pi}{sup {+-}}. The data sample corresponds to 384 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric B-factory at SLAC. They measure the CP-violating asymmetry {Alpha}{sub CP}{sup a{sub 1}{pi}} = -0.07 {+-} 0.07 {+-} 0.02, the mixing-induced CP violation parameter S{sub a{sub 1}{pi}} = 0.37 {+-} 0.21 {+-} 0.07, the direct Cp violation parameter C{sub a{sub 1}{pi}} = -0.10 {+-} 0.15 {+-} 0.09, and the parameters {Delta}C{sub a{sub 1}{pi}} = 0.26 {+-} 0.15 {+-} 0…

Search for the decay B0→a1±ρ∓

We present a search for the rare B-meson decay B-0 -> a(1)(+/-)rho(-/+) with a(1)(+/-)->pi(+)pi(-)pi(+/-). We use (110 +/- 1.2)x10(6) Upsilon(4S)-> B (B) over bar decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We obtain an upper limit of 30x10(-6) (90%C.L.) for the branching fraction product B(B-0 -> a(1)(+/-)rho(-/+))B(a(1)(+/-)->pi(+)pi(-)pi(+/-)), where we assume that the a(1)(+/-) decays exclusively to rho(0)pi(+/-).

A search for new physics in dijet mass and angular distributions in pp collisions at [subscript √s=7] TeV measured with the ATLAS detector

A search for new interactions and resonances produced in LHC proton–proton (pp) collisions at a centre-of-mass energy ps = 7 TeV was performed with the ATLAS detector. Using a dataset with an integrated luminosity of 36 pb−1, dijet mass and angular distributions were measured up to dijet masses of 3.5 TeV and were found to be in good agreement with Standard Model predictions. This analysis sets limits at 95% CL on various models for new physics: an excited quark is excluded for mass between 0.60 and 2.64 TeV, an axigluon hypothesis is excluded for axigluon masses between 0.60 and 2.10 TeV and quantum black holes are excluded in models with six extra space–time dimensions for quantum gravity…

Commissioning of the ATLAS Muon Spectrometer with cosmic rays

The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector i…

Measurement ofB→K*(892)γBranching Fractions andCPand Isospin Asymmetries

We present an analysis of the decays B-0 -> K-*0(892)gamma and B+-> K*+(892)gamma using a sample of about 383x10(6) BB events collected with the BABAR detector at the PEP-II asymmetric energy B factory. We measure the branching fractions B(B-0 -> K-*0 gamma)=(4.47 +/- 0.10 +/- 0.16)x10(-5) and B(B+-> K*+gamma)=(4.22 +/- 0.14 +/- 0.16)x10(-5). We constrain the direct CP asymmetry to be -0.033 K-*gamma)< 0.028 and the isospin asymmetry to be 0.017 <Delta(0-)< 0.116, where the limits are determined by the 90% confidence interval and include both the statistical and systematic uncertainties.

Measurement of theB±→ρ±π0branching fraction and directCPasymmetry

We present improved measurements of the branching fraction and CP asymmetry for the process B±→ρ±π0. The data sample corresponding to 211fb-1 comprises 232×106 Υ(4S)→BB decays collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. The yield and CP asymmetry are measured using an extended maximum likelihood fitting method. The branching fraction and CP asymmetry are found to be B(B±→ρ±π0)=[10.2±1.4(stat)±0.9(syst)] ×10-6 and ACP(B±→ρ±π0)=-0.01±0.13(stat) ±0.02(syst). © 2007 The American Physical Society.

Measurements of theB→D*form factors using the decayB¯0→D*+e−ν¯e

We measure the dependence of (B) over bar (0)-> D(*+)e(-)(B) over bar (e) on the decay angles and momentum transfer. The data sample consists of similar to 86x10(6) B (B) over bar -pairs accumulated on the Upsilon(4S) resonance by the BABAR detector at the asymmetric e(+)e(-) collider PEP-II. We specify the three form factors by two ratios R-1 and R-2, and by a single parameter rho(2) characterizing the polynomial representing h(A1), the function which describes the momentum-transfer dependence of the form factor A(1). We determine R-1, R-2, and rho(2) using an unbinned maximum likelihood fit to the full decay distribution. The results are R-1=1.396 +/- 0.060 +/- 0.035 +/- 0.027, R-2=0.885 …

Search for TeV-scale gravity signatures in final states with leptons and jets with the ATLAS detector at s=7 TeV

A search for physics beyond the Standard Model, in final states with at least one high transverse momentum charged lepton (electron or muon) and two additional high transverse momentum leptons or jets, is performed using 3.2 fb−1 of proton–proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015 at √s = 13 TeV. The upper end of the distribution of the scalar sum of the transverse momenta of leptons and jets is sensitive to the production of high-mass objects. No excess of events beyond Standard Model predictions is observed. Exclusion limits are set for models of microscopic black holes with two to six extra dimensions.

Readiness of the ATLAS liquid argon calorimeter for LHC collisions

The ATLAS liquid argon calorimeter has been operating continuously since August 2006. At this time, only part of the calorimeter was readout, but since the beginning of 2008, all calorimeter cells have been connected to the ATLAS readout system in preparation for LHC collisions. This paper gives an overview of the liquid argon calorimeter performance measured in situ with random triggers, calibration data, cosmic muons, and LHC beam splash events. Results on the detector operation, timing perfor-mance, electronics noise, and gain stability are presented. High energy deposits from radiative cosmic muons and beam splash events allow to check the intrinsic constant term of the energy resolutio…

Study ofb→cinterference in the decayB−→[K+π−]DK*−

Using a sample of 232 x 10^6 Upsilon(4S)--> B B-bar events collected with the BABAR detector at the PEP-II B-factory we study the decay B- --> [K+ pi-]_D K*- where the K+ pi- is either from a Cabibbo-favored D0-bar decay or doubly-suppressed D0 decay. We measure two observables that are sensitive to the CKM angle gamma; the ratio R of the charge-averaged branching fractions for the suppressed and favored decays; and the charge asymmetry A of the suppressed decays: R=0.046 +/- 0.031(stat.) +/- 0.008(syst.) A=-0.22 +/- 0.61(stat.) +/- 0.17(syst.).

Structure at 2175 MeV ine+e−→ϕf0(980)observed via initial-state radiation

We study the initial-state-radiation processes e+e-→K+K-π+π- γ and e+e-→K+K-π0π0γ using an integrated luminosity of 232fb-1 collected at the Υ(4S) mass with the BABAR detector at SLAC. Even though these reactions are dominated by intermediate states with excited kaons, we are able to study for the first time the cross section for e+e-→ (1020)f0(980) as a function of center-of-mass energy. We observe a structure near threshold consistent with a 1 - resonance with mass m=2.175±0. 010±0.015GeV/c2 and width Γ=58±16±20MeV. We observe no Y(4260) signal and set a limit of BY→ π+π-•ΓeeY<0. 4eV (90% confidence level), which excludes some models. © 2006 The American Physical Society.

Dalitz plot analysis of B−→D+π−π−

We report on a Dalitz plot analysis of B- -> D+pi(-)pi(-) decays, based on a sample of about 383 x 10(6) Y(4S) -> B (B) over bar decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We find the total branching fraction of the three-body decay: B(B- -> D+ pi(-)pi(-)) = (1.08 +/- 0.03 +/- 0.05) x 10(-3). We observe the established D-2*(0) and confirm the existence of D-0*(0) in their decays to D+pi(-), where the D-2*(0) and D-0*(0) are the 2(+) and 0(+) c (u) over bar P-wave states, respectively. We measure the masses and widths of D-2*(0) and D-0*(0) to be: m(D2)*(0) = (2460.4 +/- 1.2 +/- 1.2 +/- 1.9) MeV/c(2), Gamma(D2*0) = (41.8 +/- 2.5 +/- 2.1 +/- 2.…

Search forCPViolation in the DecaysD0→K−K+andD0→π−π+

We report a search for CP violation in the decay modes D±→KS0K±, Ds±→KS0K±, and Ds±→KS0π± using a data set corresponding to an integrated luminosity of 469  fb-1 collected with the BABAR detector at the PEP-II asymmetric energy e+e- storage rings. The decay rate CP asymmetries, ACP, are determined to be (+0.13±0.36(stat)±0.25(syst))%, (-0.05±0.23(stat)±0.24(syst))%, and (+0.6±2.0(stat)±0.3(syst))%, respectively. These measurements are consistent with zero, and also with the Standard Model prediction [(-0.332±0.006)% for the D±→KS0K± and Ds±→KS0K± modes, and (+0.332±0.006)% for the Ds±→KS0π± mode]. They are the most precise determinations to date.

Measurement of Time-DependentCP-Violating Asymmetries inB0→ϕKS0,K+K−KS0, andη′KS0Decays

We present an improved measurement of $CP$-violation parameters in ${B}^{0}\ensuremath{\rightarrow}\ensuremath{\phi}{K}_{S}^{0}$, ${K}^{+}{K}^{\ensuremath{-}}{K}_{S}^{0}$, and ${\ensuremath{\eta}}^{\ensuremath{'}}{K}_{S}^{0}$ decays based on a $140\text{ }{\mathrm{f}\mathrm{b}}^{\ensuremath{-}1}$ data sample collected at the $\ensuremath{\Upsilon}(4S)$ resonance with the Belle detector at the KEKB energy-asymmetric ${e}^{+}{e}^{\ensuremath{-}}$ collider. One neutral $B$ meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying $B$ meson is identified from its decay products. $CP$-violation parameters for each of the three modes are obtained from…

Search for second generation scalar leptoquarks in $pp$ collisions at $\sqrt{s}=7$ TeV with the ATLAS detector

The results of a search for the production of second generation scalar leptoquarks are presented for final states consisting of either two muons and at least two jets or a muon plus missing transverse momentum and at least two jets. A total of 1.03 fb−1 integrated luminosity of proton-proton collision data produced by the Large Hadron Collider at \(\sqrt{s}=7~\mbox{TeV}\) and recorded by the ATLAS detector is used for the search. The event yields in the signal regions are found to be consistent with the Standard Model background expectations. The production of second generation leptoquarks is excluded for a leptoquark mass mLQ<594 (685) GeV at 95 % confidence level, for a branching ratio of…

Search for Direct Top Squark Pair Production in Final States with One Isolated Lepton, Jets, and Missing Transverse Momentum ins=7  TeVppCollisions Using4.7  fb−1of ATLAS Data

A search is presented for direct top squark pair production in final states with one isolated electron or muon, jets, and missing transverse momentum in proton-proton collisions at root s = 7 TeV. The measurement is based on 4.7 fb(-1) of data collected with the ATLAS detector at the LHC. Each top squark is assumed to decay to a top quark and the lightest supersymmetric particle (LSP). The data are found to be consistent with standard model expectations. Top squark masses between 230 GeV and 440 GeV are excluded with 95% confidence for massless LSPs, and top squark masses around 400 GeV are excluded for LSP masses up to 125 GeV.

Search for Lepton Flavor Violation in the Decayτ±→e±γ

A search for the non-conservation of lepton flavor in the decay {tau}{sup {+-}} {yields} e{sup {+-}}{gamma} has been performed with 2.07 x 10{sup 8} e{sup +}e{sup -} {yields} {tau}{sup +}{tau}{sup -} events collected by the BABAR detector at the PEP-II storage ring at a center-of-mass energy near 10.58 GeV. They find no evidence for a signal and set an upper limit on the branching ratio of {Beta}({tau}{sup {+-}} {yields} e{sup {+-}}{gamma}) < 1.1 x 10{sup -7} at 90% confidence level.

Measurement of decay amplitudes ofB→J/ψK*,ψ(2S)K*, andχc1K*with an angular analysis

We perform the first three-dimensional measurement of the amplitudes of B→ψ(2S)K* and B→χc1K* decays and update our previous measurement for B→J/ψK*. We use a data sample collected with the BABAR detector at the PEP-II storage ring, corresponding to 232×106 BB pairs. The longitudinal polarization of decays involving a JPC=1++ χc1 meson is found to be larger than that with a 1 - J/ψ or ψ(2S) meson. No direct CP-violating charge asymmetry is observed. © 2007 The American Physical Society.

Search for pair production of first or second generation leptoquarks in proton-proton collisions ats=7  TeVusing the ATLAS detector at the LHC

This paper describes searches for the pair production of first or second generation scalar leptoquarks using 35 pb(-1) of proton-proton collision data recorded by the ATLAS detector at root s = 7 TeV. Leptoquarks are searched in events with two oppositely-charged muons or electrons and at least two jets, and in events with one muon or electron, missing transverse momentum and at least two jets. After event selection, the observed yields are consistent with the predicted backgrounds. Leptoquark production is excluded at the 95% CL for masses M-LQ < 376 (319) GeV and M-LQ < 422 (362) GeV for first and second generation scalar leptoquarks, respectively, when assuming the branching fraction of …

Search for pair-produced heavy quarks decaying toWqin the two-lepton channel at(s)=7  TeVwith the ATLAS detector

A search is presented for heavy-quark pair production (Q (Q) over bar) under the decay hypothesis Q (Q) over bar -> W(+)qW(-)(q) over bar with q = d, s, b for up-type Q or q = u, c for down-type ...

Search for the Standard Model Higgs Boson in the Diphoton Decay Channel with4.9  fb−1ofppCollision Data ats=7  TeVwith ATLAS

A search for the standard model Higgs boson is performed in the diphoton decay channel. The data used correspond to an integrated luminosity of 4.9  fb-1 collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of √s=7  TeV. In the diphoton mass range 110–150 GeV, the largest excess with respect to the background-only hypothesis is observed at 126.5 GeV, with a local significance of 2.8 standard deviations. Taking the look-elsewhere effect into account in the range 110–150 GeV, this significance becomes 1.5 standard deviations. The standard model Higgs boson is excluded at 95% confidence level in the mass ranges of 113–115 GeV and…

Study ofB-meson decays toηcK(*),ηc(2S)K(*), andηcγK(*)

We study two-body B-meson decays to a charmonium state (eta(c), eta(c)(2S) or h(c)) and a K+ or K-*0(892) meson using a sample of 349 fb(-1) of data collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. We measure B(B-0 -> eta K-c*(0)) = (5.7 +/- 0.6(stat) +/- 0.9(syst)) x 10(-4), B(B-0 -> eta(c)(2S)K*(0)) h(c)K(+)) x B(h(c) -> eta(c)gamma) h(c)K*(0)) x B(h(c) -> eta(c)gamma) K (K) over bar pi) = (1.9 +/- 0.4(stat) +/- 1.1(syst))%. We also measure the mass and width of the eta(c) meson to be m(eta(c)) = (2985.8 +/- 1.5(stat) +/- 3.1(syst)) MeV/c(2) and Gamma(eta(c)) = (36.3(-3.6)(+3.7)(stat) +/- 4.4(syst)) MeV.

Measurements of branching fractions, rate asymmetries, and angular distributions in the rare decays B→K + - and B→K* + -

We present measurements of the flavor-changing neutral current decays B -> K center dot(+)center dot(-) and B -> K-*center dot(+)center dot(-), where center dot(+)center dot(-) is either an e(+)e(-) or mu(+)mu(-) pair. The data sample comprises 229x10(6) Upsilon(4S)-> B (B) over bar decays collected with the BABAR detector at the PEP-II e(+)e(-) storage ring. Flavor-changing neutral current decays are highly suppressed in the standard model and their predicted properties could be significantly modified by new physics at the electroweak scale. We measure the branching fractions B(B -> K center dot(+)center dot(-))=(0.34 +/- 0.07 +/- 0.02)x10(-6), B(B -> K-*center dot(+)center dot(-))=(0.78(-…

Angular distributions in the decay B -> K*l(+)l(-)

We use a sample of 384 million BBbar events collected with the Babar detector at the PEP-II e+e- collider to study angular distributions in the rare decays B -> K* l+l-, where l+l- is either e+e- or mu+mu-. For low dilepton invariant masses, m(l+l-)3.2$ GeV/c^2, we measure AFB=0.76 (+0.52,-0.32) +/- 0.07 FL=0.71 (+0.20,-0.22) +/- 0.04.

DirectCPViolating Asymmetry inB0→K+π−Decays

We present an updated search for direct CP violation in the decay B0 -> K+pi-. Using 227 million Y(4S) -> BBbar decays collected with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we observe a total signal yield of n(K-pi+) + n(K+pi-) = 1606 +- 51 decays and measure the asymmetry [n(K-pi+)-n(K+pi-)]/[n(K-p+-)+n(K+pi-)] = -0.133+-0.030 (stat) +- 0.009 (syst). This measurement establishes direct CP violation in the B0 meson system at the level of 4.2 standard deviations.

Measurement of W ± Z production in proton-proton collisions at √s =7 TeV with the ATLAS detector

A study of W±Z production in proton-proton collisions at √s=7 TeV is presented using data corresponding to an integrated luminosity of 4.6 fb−1 collected with the ATLAS detector at the Large Hadron Collider in 2011. In total, 317 candidates, with a background expectation of 68±10 events, are observed in double-leptonic decay final states with electrons, muons and missing transverse momentum. The total cross-section is determined to be σtotWZ=19.0+1.4−1.3(stat.)±0.9(syst.)±0.4(lumi.) pb, consistent with the Standard Model expectation of 17.6+1.1−1.0 pb. Limits on anomalous triple gauge boson couplings are derived using the transverse momentum spectrum of Z bosons in the selected events. The …

Search for prompt production ofχcandX(3872)ine+e−annihilations

We have searched for prompt production of χc1, χc2 and X(3872) in continuum e+e- annihilations using a 386fb-1 data sample collected around s=10.6GeV with the BABAR detector using the γJ/ψ decay mode. After accounting for the feed-down from ψ(2S)→γχc1,2, no significant signal for prompt χc1,2 production is observed. We present improved upper limits at 90% confidence level on the production cross sections of 77fb for χc1 and 79fb for χc2, for events where the χc momentum exceeds 2.0 GeV and there are at least three additional charged tracks. These limits are consistent with NRQCD predictions. We also set an upper limit on the prompt production of X(3872) through the decay X(3872)→γJ/ψ. © 200…

Measurements of the Absolute Branching Fractions of B± →k±Xc c

A study of the two-body decays B±→XccK±, where Xcc refers to one charmonium state, is reported by the BABAR Collaboration using a data sample of 424 fb-1. The absolute determination of branching fractions for these decays are significantly improved compared to previous BABAR measurements. Evidence is found for the decay B+→X(3872)K+ at the 3σ level. The absolute branching fraction B[B+→X(3872)K+]=[2.1±0.6(stat)±0.3(syst)]×10-4 is measured for the first time. It follows that B[X(3872)→J/ψπ+π-]=(4.1±1.3)%, supporting the hypothesis of a molecular component for this resonance.

Observation and polarization measurement ofB0→a1(1260)+a1(1260)−decay

We present measurements of the branching fraction B and longitudinal polarization fraction fL for B0→a1(1260)+a1(1260)- decays, with a1(1260)±→π-π+π±. The data sample, collected with the BABAR detector at the SLAC National Accelerator Laboratory, represents 465×106 produced BB pairs. We measure B(B0→a1(1260)+a1(1260)-)×[B(a1(1260)+→π-π+π+)]2= (11.8±2.6±1.6)×10-6 and fL=0.31±0.22±0.10, where the first uncertainty is statistical and the second systematic. The decay mode is measured with a significance of 5.0 standard deviations including systematic uncertainties.

Search for the DecayB+→K+τ∓μ±

We present a search for the lepton flavor violating decay B+-->K+ tau-/+ mu+/- using 383 x 10;{6} BB[over ] events collected by the BABAR experiment. The branching fraction for this decay can be substantially enhanced in new physics models. The kinematics of the tau from the signal B decay are inferred from the K+, mu, and other B in the event, which is fully reconstructed in one of a variety of hadronic decay modes, allowing the signal B candidate to be fully reconstructed. We observe no excess of events over the expected background and set a limit of B(B+-->K+ tau mu)<7.7 x 10(-5) at 90% confidence level, where the branching fraction is for the sum of the K+ tau- mu+ and K+ tau+mu- final …

Search for diphoton events with large missing transverse momentum in 7 TeV proton-proton collision data with the ATLAS detector

A search for diphoton events with large missing transverse momentum has been performed using proton–proton collision data at √s = 7 TeV recorded with the ATLAS detector, corresponding to an integrated luminosity of 4.8 fb[superscript −1]. No excess of events was observed above the Standard Model prediction and model-dependent 95% confidence level exclusion limits are set. In the context of a generalised model of gauge-mediated supersymmetry breaking with a bino-like lightest neutralino of mass above 50 GeV, gluinos (squarks) below 1.07 TeV (0.87 TeV) are excluded, while a breaking scale Λ below 196 TeV is excluded for a minimal model of gauge-mediated supersymmetry breaking. For a specific …

Search for charged Higgs bosons through the violation of lepton universality in t(t)over-bar events using pp collision data at root s=7 TeV with the ATLAS experiment

In several extensions of the Standard Model, the top quark can decay into a bottom quark and a light charged Higgs boson H [superscript +], t → bH [superscript +], in addition to the Standard Model decay t → bW. Since W bosons decay to the three lepton generations equally, while H [superscript +] may predominantly decay into τν, charged Higgs bosons can be searched for using the violation of lepton universality in top quark decays. The analysis in this paper is based on 4.6 fb[superscript −1] of proton-proton collision data at √s = 7 TeV collected by the ATLAS experiment at the Large Hadron Collider. Signatures containing leptons (e or μ) and/or a hadronically decaying τ (τ [subscript had])…

Improved Measurement ofB+→ρ+ρ0and Determination of the Quark-Mixing Phase Angleα

We present improved measurements of the branching fraction ${\cal B}$, the longitudinal polarization fraction $f_L$, and the direct {\ensuremath{CP}\xspace} asymmetry {\ensuremath{{\cal A}_{CP}}\xspace} in the $B$ meson decay channel $B^+\to\rho^+\rho^0$. The data sample was collected with the {{\slshape B\kern-0.1em{\smaller A}\kern-0.1em B\kern-0.1em{\smaller A\kern-0.2em R}}} detector at SLAC. The results are ${\cal B} (\Bp\ra\rprz)=(23.7\pm1.4\pm1.4)\times10^{-6}$, $f_L=0.950\pm0.015\pm0.006$, and $\Acp=-0.054\pm0.055\pm0.010$, where the uncertainties are statistical and systematic, respectively. Based on these results, we perform an isospin analysis and determine the CKM weak phase ang…

Observation ofBMeson Decays tob1πandb1K

We present the results of searches for decays of B mesons to final states with a b_1 meson and a charged pion or kaon. The data, collected with the BaBar detector at the Stanford Linear Accelerator Center, represent 382 million B-Bbar pairs produced in e+e- annihilation. The results for the branching fractions are, in units of 10^{-6}, B(B+ -> b1^0 pi+) = 6.7 +/- 1.7 +/- 1.0 (4.0 sigma), B(B+ -> b1^0 K+ = 9.1+/- 1.7+/- 1.0 (5.3 sigma), B(B0 -> b1^-/+ pi^+/-) = 10.9 +/- 1.2 +/- 0.9 (8.9 sigma), and B(B0 -> b1^-K+) = 7.4 +/- 1.0 +/- 1.0 (6.1 sigma), with the assumption that B(b_1 -> omega pi)=1. We also measure charge and flavor asymmetries Ach(B+ -> b1^0 pi+) = 0.05 +/- 0.16 +/- 0.02, Ach(B+…

Measurement of the inclusiveW±andZ/γ*cross sections in theeandμdecay channels inppcollisions ats=7  TeVwith the ATLAS detector

The production cross sections of the inclusive Drell-Yan processes W-+/- -> l nu and Z/gamma* -> ll (l = e, mu) are measured in proton-proton collisions at root s = 7 TeV with the ATLAS detector. The cross sections are reported integrated over a fiducial kinematic range, extrapolated to the full range, and also evaluated differentially as a function of the W decay lepton pseudorapidity and the Z boson rapidity, respectively. Based on an integrated luminosity of about 35 pb(-1) collected in 2010, the precision of these measurements reaches a few percent. The integrated and the differential W-+/- and Z/gamma* cross sections in the e and mu channels are combined, and compared with perturbative…

Determination of the Branching Fraction forB→XcℓνDecays and of|Vcb|from Hadronic-Mass and Lepton-Energy Moments

We determine the inclusive B --> Xc l nu branching fraction, the CKM matrix element |Vcb|, and other heavy-quark parameters from a simultaneous fit to moments of the hadronic-mass and lepton-energy distributions in semileptonic B-meson decays, measured as a function of the lower limit on the lepton energy, using data recorded with the BABAR detector. Using Heavy Quark Expansions (HQEs) to order 1/mb^3, we extract BR_cenu=(10.61 +- 0.16(exp) +- 0.06(HQE))% and |Vcb| = (41.4 +- 0.4(exp) +- 0.4(HQE) +- 0.6(th)) 10^-3. The stated errors refer to the experimental, HQE, and additional theoretical uncertainties.

Search for theZ(4430)−atBABAR

We report the results of a search for Z(4430)^- decay to J/Ψ π^- or Ψ(2S)π^- in B(^-.0)→ J/Ψ π^-K^(0.+) and B^(-.0) → Ψ(2S)π^-K^(0.+) decays. The data were collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e^+e^- collider operating at center-of-mass energy 10.58 GeV, and the sample corresponds to an integrated luminosity of 413 fb^(-1). Each K π^- mass distribution exhibits clear K^*(892) and K_2^*(1430) signals, and the efficiency-corrected spectrum is well described by a superposition of the associated Breit-Wigner intensity distributions, together with an S-wave contribution obtained from the LASS I=1/2 K π^- scattering amplitude measurements. Each K π^- angular dist…

Measurements of the Branching Fraction andCP-Violation Asymmetries inB0→f0(980)KS0

The authors present measurements of the branching fraction and CP-violating asymmetries in the decay B{sup 0} {yields} f{sub 0}(980)K{sub S}{sup 0}. The results are obtained from a data sample of 123 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays. From a time-dependent maximum likelihood fit they measure the branching fraction {Beta}(B{sup 0} {yields} f{sub 0}(980)({yields}{Pi}{sup +}{pi}{sup 0})K{sup 0}) = (6.0 {+-} 0.9 {+-} 0.6 {+-} 1.2) x 10{sup -6}, the mixing-induced CP violation parameter S = 1.62{sub -0.51}{sup +0.56} {+-} 0.09 {+-} 0.04 and the direct CP violation parameter C = 0.27 {+-} 0.36 {+-} 0.10 {+-} 0.07, where the first errors are statistical, the second systematic and …

Search forB0Decays to Invisible Final States and toνν¯γ

We establish upper limits on branching fractions for B0 decays to final states where the decay products are purely invisible (i.e., no observable final state particles) and for B0 decays to nunugamma. Within the standard model, these decays have branching fractions that are below current experimental sensitivity, but various models of physics beyond the standard model predict significant contributions from these channels. Using 88.5 x 10(6) BB pairs collected at the Upsilon(4S) resonance by the BABAR experiment at the PEP-II e(+)e- storage ring at the Stanford Linear Accelerator Center, we establish upper limits at the 90% confidence level of 22 x 10(-5) for the branching fraction of B0-->i…

Measurements ofB→{π,η,η′}lνlBranching Fractions and Determination of|Vub|with Semileptonically TaggedBMesons

We report measurements of branching fractions for the decays B-->Plnu_{l}, where P are the pseudoscalar charmless mesons pi;{-}, pi;{0}, eta and eta;{'}, based on 348 fb;{-1} of data collected with the BABAR detector, using B0 and B+ mesons found in the recoil of a second B meson decaying as B-->D;{(*)}lnu_{l}. Assuming isospin symmetry, we combine pionic branching fractions to obtain B(B;{0}-->pi;{-}l;{+}nu_{l})=(1.54+/-0.17_{(stat)}+/-0.09_{(syst)})x10;{-4}; we find 3.2sigma evidence of the decay B;{+}-->etal;{+}nu_{l} and measure its branching fraction to be (0.64+/-0.20_{(stat)}+/-0.03_{(syst)})x10;{-4}, and determine B(B;{+}-->eta;{'}l;{+}nu_{l})<0.47x10;{-4} to 90% confidence level. U…

Measurement of the Time-DependentCPAsymmetry in theB0→ϕK0Decay

The authors present a measurement of the time-dependent CP asymmetry for the neutral B-meson decay B{sup 0} {yields} {phi} K{sup 0}. They use a sample of approximately 114 million B-meson pairs taken at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II B-meson Factory at SLAC. They reconstruct the CP eigenstates {phi}K{sub S}{sup 0} and {phi}K{sub L}{sup 0} where {phi} {yields} K{sup +}K{sup -}, K{sub S}{sup 0} {yields} {pi}{sup +}{pi}{sup -}, and K{sub L}{sup 0} is observed via its hadronic interactions. The other B meson in the event is tagged as either a B{sup 0} or {bar B}{sup 0} from its decay products. The values of the CP-violation parameters are S{sub {phi}K} = 0.47 …

Measurement of Dijet Azimuthal Decorrelations inppCollisions ats=7  TeV

Azimuthal decorrelations between the two central jets with the largest transverse momenta are sensitive to the dynamics of events with multiple jets. We present a measurement of the normalized differential cross section based on the full data set ( integral Ldt = 36 pb(-1)) acquired by the ATLAS detector during the 2010 root s = 7 TeV proton-proton run of the LHC. The measured distributions include jets with transverse momenta up to 1.3 TeV, probing perturbative QCD in a high-energy regime.

Search for the decayB+→τ+ντ

We search for the rare leptonic decay B^+ → τ^+ν_τ in a sample of 232 × 10^6 BB pairs collected with the BABAR detector at the SLAC PEP-II B-Factory. Signal events are selected by examining the properties of the B meson recoiling against the semileptonic decay B^- → D^9*0)l^-ν_ l. We find no evidence for a signal and set an upper limit on the branching fraction of B(B^+ → τ^+ν_τ)<2.8 × 10^9-4) at the 90% confidence level. We combine this result with a previous, statistically independent BABAR search for B+→τ+ντ to give an upper limit of B(B^+ → τ^+ν_τ)<2.6 × 10^(-4) at the 90% confidence level.

Measurement of the WW cross section in s=7 TeV pp collisions with the ATLAS detector and limits on anomalous gauge couplings

This Letter reports a measurement of the W W production cross section in root s = 7 TeV pp collisions using data corresponding to an integrated luminosity of 1.02 fb(-1) collected with the ATLAS de ...

Search for excited electrons and muons in root s=8 TeV proton-proton collisions with the ATLAS detector

The ATLAS detector at the Large Hadron Collider is used to search for excited electrons and excited muons in the channel pp → ℓℓ* → ℓℓγ, assuming that excited leptons are produced via contact interactions. The analysis is based on 13 fb[superscript −1] of pp collisions at a centre-of-mass energy of 8 TeV. No evidence for excited leptons is found, and a limit is set at the 95% credibility level on the cross section times branching ratio as a function of the excited-lepton mass m[subscript ℓ*]. For m[subscript ℓ*] ≥ 0.8 TeV, the respective upper limits on σB(ℓ* → ℓγ) are 0.75 and 0.90 fb for the e* and μ* searches. Limits on σB are converted into lower bounds on the compositeness scale Λ. In …

Study ofBMeson Decays with Excitedηandη′Mesons

Using 383 million B{bar B} pairs from the BABAR data sample, they report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to K{bar K}* or {eta}{pi}{pi} final states with mass in the range (1.2-1.8) GeV/c{sup 2}. They observe a significant enhancement at the low K{bar K}* invariant mass which is interpreted as B{sup +} {yields} {eta}(1475)K{sup +}, find evidence for the decay B{sup +} {yields} {eta}(1295)K{sup +}, and place upper limits on the decays B{sup +} {yields} {eta}(1405)K{sup +}, B{sup +} {yields} f{sub 1}(1285)K{sup +}, B{sup +} {yields} f{sub 1}(1420)K{sup +}, and B{sup +} {yields} {phi}(1680)K{…

Measurement of the branching fraction andΛ¯polarization inB0→Λ¯pπ−

We present a measurement of the B0 --> Lambda-bar p pi- branching fraction performed using the BaBar detector at the PEP-II asymmetric e+e- collider. Based on a sample of 467 million BB-bar pairs we measure B(B0 --> Lambda-bar p pi-) = [3.07 pm 0.31 (stat.) pm 0.23 (syst.)] x 10^{-6}. The measured differential spectrum as a function of the dibaryon invariant mass m(Lambda p) shows a near-threshold enhancement similar to that observed in other baryonic B decays. We study the Lambda-bar polarization as a function of Lambda-bar energy in the B0 rest frame (E*_Lambda) and compare it with theoretical expectations of fully longitudinally right-polarized Lambda-bar at large E*_Lambda.

Dalitz-plot analysis of the decays B±→K±π π±

We report a Dalitz-plot analysis of the charmless hadronic decays of charged B mesons to the final state K±π π±. Using a sample of 226.0±2.5 million BB̄ pairs collected by the BABAR detector, we measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for both charge-conjugate decays. We present measurements of the corresponding branching fractions and their charge asymmetries that supersede those of previous BABAR analyses. We find the charge asymmetries to be consistent with zero. © 2005 The American Physical Society.

Measurements ofΛc+branching fractions of Cabibbo-suppressed decay modes involvingΛandΣ0

We measure the branching ratios of the Cabibbo-suppressed decays $\Lambda^+_c$ $\to$ $\Lambda$ $K^+$ and $\Lambda^+_c$ $\to$ $\Sigma^{0}$ $K^+$ %(measured with improved accuracy). relative to the Cabibbo-favored decay modes $\Lambda^+_c$ $\to$ $\Lambda$ $\pi^+$ and $\Lambda^+_c$ $\to$ $\Sigma^{0}$ $\pi^+$ to be $ 0.044 \pm 0.004 ~(\textnormal{stat.})~ \pm ~0.003 \~(\textnormal{syst.})$ and $ 0.039~ \pm ~0.005 ~(\textnormal{stat.})~ \pm \~0.003 ~(\textnormal{syst.})$, respectively. We set an upper limit on the branching ratio at 90 % confidence level for $\Lambda^+_c$ $\to$ $\Lambda$ $K^+ \pi^+ \pi^-$ to be $ 4.1 \times ~10^{-2}$ relative to $\Lambda^+_c$ $\to$ $\Lambda$ $\pi^+$ and for $\La…

Search forB0→K*+K*−

The authors report the results of a search for the decay B{sup 0} {yields} K*{sup +}K*{sup -} with a sample of 454 {+-} 5 million B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the Stanford Linear Accelerator Center. They obtain an upper limit at the 90% confidence level on the branching fraction for {Beta}(B{sup 0} {yields} K*{sup +}K*{sup -}) < 2.0 x 10{sup -6}, assuming the decay is fully longitudinally polarized.

Measurement of time dependentCPasymmetry parameters inB0meson decays toωKS0,η′K0, andπ0KS0

We present measurements of the time-dependent CP-violation parameters S and C in the decays B-0 -> omega K-S(0), B-0 -> eta'K-0, reconstructed as eta'K-S(0) and eta'K-L(0), and B-0 -> pi K-0(S)0. The data sample corresponds to the full BABAR dataset of 467 x 10(6) B (B) over bar pairs produced at the PEP-II asymmetric-energy e(+)e(-) collider at the Stanford Linear Accelerator Center. The results are S-omega KS0 = 0.55(-0.29)(+0.26) +/- 0.02, C-omega KS0 = 0.52(-0.20)(+0.22) +/- 0.03, S-eta'K0 = 0.57 +/- 0.08 +/- 0.02, C-eta'K0 = 0.08 +/- 0.06 +/- 0.02, S-pi 0KS0 = 0.55 +/- 0.20 +/- 0.03, and C-pi 0KS0 = 0.13 +/- 0.13 +/- 0.03, where the first errors are statistical and the second systemati…

Search for the reactionse+e−→μ+τ−ande+e−→e+τ−

We report on a search for the lepton- flavor- violating processes e(+) e(-) -> mu(+) tau(-) and e(+) e(-) -> e(+) tau(-). The data sample corresponds to an integrated luminosity of 211 fb(-1) recorded by the BABAR experiment at the SLAC PEP-II asymmetric-energy B Factory at a center-of-mass energy of root s = 10.58 GeV. We find no evidence for a signal and set the 90% confidence level upper limits on the cross sections to be sigma (mu tau) < 3.8 fb and sigma(e tau) < 9.2 fb. The ratio of the cross sections with respect to the dimuon cross section are measured to be sigma (mu tau)/sigma (mu mu) < 3.4 X 10(-6) and sigma (e tau)/sigma (mu mu) < 8.2 X 10(-6).

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at $\sqrt{s}=7$  TeV

A measurement of the production cross-section for top quark pairs($\ttbar$) in $pp$ collisions at $\sqrt{s}=7 \TeV$ is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-$\ttbar$ Standard Model processes are estimated using data-driv…

Measurement of multi-jet cross sections in proton-proton collisions at a 7 TeV center-of-mass energy

Inclusive multi-jet production is studied in proton–proton collisions at a center-of-mass energy of 7 TeV, using the ATLAS detector. The data sample corresponds to an integrated luminosity of 2.4 pb−1. Results on multi-jet cross sections are presented and compared to both leading-order plus parton-shower Monte Carlo predictions and to next-to-leading-order QCD calculations.

Search forD0−D¯0mixing using doubly flavor tagged semileptonic decay modes

We have searched for D0-D0 mixing in D*+→π+D0 decays with D0→K(*)eν in a sample of e+e-→cc events produced near 10.58 GeV. The charge of the slow pion from charged D* decay tags the charm flavor at production, and it is required to be consistent with the flavor of a fully reconstructed second charm decay in the same event. We observe 3 mixed candidates compared to 2.85 background events expected from simulation. We ascribe a 50% systematic uncertainty to this expected background rate. We find a central value for the mixing rate of 0.4×10-4. Using a frequentist method, we set corresponding 68% and 90% confidence intervals at (-5.6,7.4)×10-4 and (-13,12)×10-4, respectively. © 2007 The America…

Study of theX(3872)andY(4260)inB0→J/ψπ+π−K0andB−→J/ψπ+π−K−decays

We present results of a search for the X(3872) in B{sup 0}{yields}X(3872)K{sub S}{sup 0},X(3872){yields}J/{psi}{pi}{sup +}{pi}{sup -}, improved measurements of B{sup -}{yields}X(3872)K{sup -}, and a study of the J/{psi}{pi}{sup +}{pi}{sup -} mass region above the X(3872). We use 232x10{sup 6} BB pairs collected at the {upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} asymmetric-energy storage rings. The results include the 90% confidence interval 1.34x10{sup -6}<B(B{sup 0}{yields}X(3872)K{sup 0},X{yields}J/{psi}{pi}{sup +}{pi}{sup -})<10.3x10{sup -6} and the branching fraction B(B{sup -}{yields}X(3872)K{sup -},X{yields}J/{psi}{pi}{sup +}{pi}{sup -})=(10.1{+-}2.5…

Vector-Tensor and Vector-Vector Decay Amplitude Analysis ofB0→φK*0

We perform an amplitude analysis of the decays B(0)-->phiK*(2)(1430)(0), phiK*(892)(0), and phi(Kpi)(0)(S-wave) with a sample of about 384x10(6) BB[over ] pairs recorded with the BABAR detector. The fractions of longitudinal polarization f(L) of the vector-tensor and vector-vector decay modes are measured to be 0.853(-0.069+0.061)+/-0.036 and 0.506+/-0.040+/-0.015, respectively. Overall, twelve parameters are measured for the vector-vector decay and seven parameters for the vector-tensor decay, including the branching fractions and parameters sensitive to CP violation.

Search for theW-exchange decaysB0→Ds(*)−Ds(*)+

We report a search for the decays B{sup 0}{yields}D{sub s}{sup -}D{sub s}{sup +}, B{sup 0}{yields}D{sub s}*{sup -}D{sub s}{sup +}, and B{sup 0}{yields}D{sub s}*{sup -}D{sub s}*{sup +} in a sample of 232x10{sup 6} {upsilon}(4S) decays to BB pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. We find no significant signal and set upper bounds for the branching fractions: B(B{sup 0}{yields}D{sub s}{sup -}D{sub s}{sup +})<1.0x10{sup -4}, B(B{sup 0}{yields}D{sub s}*{sup -}D{sub s}{sup +})<1.3x10{sup -4}, and B(B{sup 0}{yields}D{sub s}*{sup -}D{sub s}*{sup +})<2.4x10{sup -4} at 90% confidence level.

A search for t[bar over t] resonances in lepton+jets events with highly boosted top quarks collected in pp collisions at √s = 7 TeV with the ATLAS detector

A search for resonant production of high-mass top-quark pairs is performed on 2.05 fb[superscript −1] of proton-proton collisions at √s = 7 TeV collected in 2011 with the ATLAS experiment at the Large Hadron Collider. This analysis of the lepton+jets final state is specifically designed for the particular topology that arises from the decay of highly boosted top quarks. The observed t[bar over t] invariant mass spectrum is found to be compatible with the Standard Model prediction and 95% credibility level upper limits are derived on the t[bar over t] production rate through new massive states. An upper limit of 0.7 pb is set on the production cross section times branching fraction of a narr…

Exclusive Branching-Fraction Measurements of SemileptonicτDecays into Three Charged Hadrons, intoφπ−ντ, and intoφK−ντ

Using a data sample corresponding to an integrated luminosity of 342 fb(-1) collected with the BABAR detector at the SLAC PEP-II electron-positron storage ring operating at a center-of-mass energy near 10.58 GeV, we measure B(tau(-)->pi(-)pi(-)pi(+)nu(tau)(ex.K-S(0)))=(8.83 +/- 0.01 +/- 0.13)%, B(tau(-)-> K-pi(-)pi(+)nu(tau)(ex.K-S(0)))=(0.273 +/- 0.002 +/- 0.009)%, B(tau(-)-> K-pi K--(+)nu(tau))=(0.1346 +/- 0.0010 +/- 0.0036)%, and B(tau(-)-> K-K-K+nu(tau))=(1.58 +/- 0.13 +/- 0.12)x10(-5), where the uncertainties are statistical and systematic, respectively. These include significant improvements over previous measurements and a first measurement of B(tau(-)-> K-K-K+nu(tau)) in which no re…

Search for supersymmetry with jets, missing transverse momentum and at least one hadronically decaying τ lepton in proton–proton collisions at s=7 TeV with the ATLAS detector

A search for production of supersymmetric particles in final states containing jets, missing transverse momentum, and at least one hadronically decaying tau lepton is presented. The data were recor ...

Search for microscopic black holes in a like-sign dimuon final state using large track multiplicity with the ATLAS detector

A search is presented for microscopic black holes in a like-sign dimuon final state in proton-proton collisions at √s= 8 TeV. The data were collected with the ATLAS detector at the Large Hadron Collider in 2012 and correspond to an integrated luminosity of 20.3 fb-1. Using a high track multiplicity requirement, 0.6±0.2 background events from Standard Model processes are predicted and none observed. This result is interpreted in the context of low-scale gravity models and 95% CL lower limits on microscopic black hole masses are set for different model assumptions.

Study ofB→DsJ(*)+D¯(*)Decays

We report a study of D-sJ(*)(2317)(+) and D-sJ(2460)(+) meson production in B decays. We observe the decays B+--> D-sJ((*)+)(D) over bar ((*)0) and B-0 --> DsJ(*)+D(*)- with the subsequent decays D-sJ(*)(2317)(+)-->D(s)(+)pi(0), D-sJ(2460)(+)-->D(s)(+)gamma, and D-sJ(2460)(+)-->D(s)(*+)pi(0). Based on a data sample of 122.1x10(6) B(B) over bar pairs collected with the BABAR detector at the PEP-II B factory, we obtain branching fractions for these modes, including the previously unseen decays B-->(DsJ(*)+D*). In addition, we perform an angular analysis of D-sJ(2460)(+)-->D(s)(+)gamma decays to test the different D-sJ(2460)(+) spin hypotheses.

InclusiveΛc+production ine+e−annihilations ats=10.54  GeVand inΥ(4S)decays

We present measurements of the total production rates and momentum distributions of the charmed baryon Lambda(+)(c) in e(+)e(-)-> hadrons at a center-of-mass energy of 10.54 GeV and in Upsilon(4S) decays. In hadronic events at 10.54 GeV, charmed hadrons are almost exclusively leading particles in e(+)e(-)-> cc events, allowing direct studies of c-quark fragmentation. We measure a momentum distribution for Lambda(+)(c) baryons that differs significantly from those measured previously for charmed mesons. Comparing with a number of models, we find none that can describe the distribution completely. We measure an average scaled momentum of =0.574 +/- 0.009 and a total rate of N-Lambda c(qq)=0.0…

Measurement of the ratioB(B+→Xeν)/B(B0→Xeν)

We report measurements of the inclusive electron momentum spectra in decays of charged and neutral B mesons, and of the ratio of semileptonic branching fractions B(B+-> Xe nu) and B(B-0 -> Xe nu). These were performed on a sample of 231x10(6) B (B) over bar events recorded with the BABAR detector at the Upsilon(4S) resonance. Events are selected by fully reconstructing a hadronic decay of one B meson and identifying an electron among the decay products of the recoiling (B) over bar meson. We obtain B(B+-> Xe nu)/B(B-0 -> Xe nu)=1.074 +/- 0.041((stat))+/- 0.026((syst)).

Measurement of theγγ*→π0transition form factor

We study the reaction e+e- --> e+e-pi0 and measure the gamma gamma* --> pi0 transition form factor in the momentum transfer range from 4 to 40 GeV^2. The analysis is based on 442 fb^-1 of integrated luminosity collected at PEP-II with the BABAR detector at e+e- center-of-mass energies near 10.6 GeV.

Limits on tau lepton-flavor violating decays into three charged leptons

A search for the neutrinoless, lepton-flavor violating decay of the tau lepton into three charged leptons has been performed using an integrated luminosity of 468 fb(-1) collected with the BABAR detector at the PEP-II collider. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (1.8-3.3) x 10(-8) at 90% confidence level.

Measurement of underlying event characteristics using charged particles inppcollisions ats=900  GeVand 7 TeV with the ATLAS detector

Measurements of charged particle distributions, sensitive to the underlying event, have been performed with the ATLAS detector at the LHC. The measurements are based on data collected using a minimum-bias trigger to select proton-proton collisions at center-of-mass energies of 900 GeV and 7 TeV. The "underlying event" is defined as those aspects of a hadronic interaction attributed not to the hard scattering process, but rather to the accompanying interactions of the rest of the proton. Three regions are defined in azimuthal angle with respect to the highest transverse momentum charged particle in the event, such that the region transverse to the dominant momentum-flow is most sensitive to …

Search for a Heavy Particle Decaying into an Electron and a Muon with the ATLAS Detector ins=7  TeVppcollisions at the LHC

This Letter presents the first search for a heavy particle decaying into an e(+/-)mu(-/+) final state in root s = 7 TeV pp collisions at the LHC. The data were recorded by the ATLAS detector during 2010 and correspond to a total integrated luminosity of 35 pb(-1). No excess above the standard model background expectation is observed. Exclusions at 95% confidence level are placed on two representative models. In an R-parity violating supersymmetric model, tau sneutrinos with a mass below 0.75 TeV are excluded, assuming all R-parity violating couplings are zero except lambda(311)' = 0.11 and lambda(312) = 0.07. In a lepton flavor violating model, a Z'-like vector boson with masses of 0.70-1.0…

Search forB+→X(3872)K+,X(3872)→J/ψγ

In a study of B+ --> J/psi gamma K+ decays, we find evidence for the radiative decay X(3872) --> J/psi gamma with a statistical significance of 3.4 sigma. We measure the product of branching fractions BF(B+ --> X(3872) K+).BF(X(3872) --> J/psi gamma) = (3.3 +/- 1.0 +/- 0.3) x 10^-6, where the uncertainties are statistical and systematic, respectively. We also measure the branching fraction BF(B+ --> chi_c1 K+) = (4.9 +/- 0.2 +/- 0.4) x 10^-4. These results are obtained from (287+/-3) million BBar decays collected at the Y(4S) resonance with the BaBar detector at the PEP-II B Factory at SLAC.

Search for contact interactions in dilepton events from pp collisions at s=7 TeV with the ATLAS detector

This Letter presents a search for contact interactions in the dielectron and dimuon channels using data from proton-proton collisions produced by the LHC at,root s = 7 TeV and recorded by the ATLAS ...

Branching Fraction Measurements ofB+→ρ+γ,B0→ρ0γ, andB0→ωγ

The authors present a study of the decays B{sup +} {yields} {rho}{sup +}{gamma}, B{sup 0} {yields} {rho}{sup 0}{gamma}, and B{sup 0} {yields} {omega}{gamma}. The analysis is based on data containing 347 million B{bar B} events recorded with the BABAR detector at the PEP-II asymmetric B factory. They measure the branching fractions {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) = (1.10{sub -0.33}{sup +0.37} {+-} 0.09) x 10{sup -6} and {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) = (0.79{sub -0.20}{sup +0.22} {+-} 0.06) x 10{sup -6}, and set a 90% C.L. upper limit {Beta}(B{sup 0} {yields} {omega}{gamma}) < 0.78 x 10{sup -6}. They also measure the isospin-averaged branching fraction {Beta}[B {…

Evidence for the Rare DecayB+→Ds+π0

We have searched for the rare decay B+ -> D-s(+) pi(0). The analysis is based on a sample of 232 X 10(6) Y(4S) -> B (B) over bar decays collected with the BABAR detector at the SLAC PEP-II e(+)e(-) storage ring. We find 19.6 signal events, corresponding to a significance of 4.7 sigma. The extracted signal yield including statistical and systematic uncertainties is 20.1(-6.0-1.5)(+6.8+0.4) and we measure B(B+ -> D-s(+) pi(0)) = (1.5(-0.4)(+0.5) +/- 0.1 +/- 0.2) X x 10(-5), where the first uncertainty is statistical, the second is systematic, and the last is due to the uncertainty on the D-s(+) decay and its daughter decay branching fractions.

Measurements of Branching Fraction, Polarization, and Charge Asymmetry ofB±→ρ±ρ0and a Search forB±→ρ±f0(980)

We measure the branching fraction (B), polarization (f(L)), and CP asymmetry (A(CP)) of B-+/-->rho(+/-)rho(0) decays and search for the decay B-+/-->rho(+/-)f(0)(980) based on a data sample of 231.8x10(6) Upsilon(4S)-> B (B) over bar decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. In B-+/-->rho(+/-)rho(0) decays we measure B=(16.8 +/- 2.2 +/- 2.3)x10(-6), f(L)=0.905 +/- 0.042(-0.027)(+0.023), and A(CP)=-0.12 +/- 0.13 +/- 0.10, and find an upper limit on the branching fraction of B-+/-->rho(+/-)f(0)(980)(->pi(+)pi(-)) decays of 1.9x10(-6) at 90% confidence level.

Search for neutralB-meson decays toa0π,a0K,ηρ0, andηf0

We present a search for B0 decays to charmless final states involving an eta meson, a charged pion and a second charged pion or kaon. The data sample corresponds to 383x10^6 BBbar pairs collected with the BABAR detector operating at the PEP-II asymmetric-energy B Factory at SLAC. We find no significant signals and determine the following 90% C.L. upper limits: BR(B->a0-pi+) x BR(a0- -> etapi-) a0-K+) x BR(a0- -> etapi-) a0(1450)-pi+) x BR(a0(1450)- -> etapi-) a0(1450)-K+) x BR(a0(1450)- -> etapi-) etarho0) eta f0(980)) x BR(f0(980)- -> pi+pi-) < 0.4x10^-6.

Bound on the Ratio of Decay Amplitudes forB¯0→J/ψK*0andB0→J/ψK*0

We have measured the time-dependent decay rate for the process B→J/ψK*0(892) in a sample of about 88×106 Υ(4S)→BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. In this sample we study flavor-tagged events in which one neutral B meson is reconstructed in the J/ψK*0 or J/ψK *0 final state. We measure the coefficients of the cosine and sine terms in the time-dependent asymmetries for J/ψK*0 and J/ψK *0, find them to be consistent with the standard model expectations, and set upper limits at 90% confidence level (C.L.) on the decay amplitude ratios |A(B 0→J/ψK*0)|/|A(B0→J/ψK*0)|<0.26 and |A(B0→J/ψK *0)|/|A(B 0→J/ψK *0)|<0.32. For a single ratio of w…

Measurement of Time-DependentCPAsymmetries inB0→D(*)±D∓Decays

We present updated results on time-dependent CP asymmetries in fully reconstructed B-0 -> D-(*)+/-pi(-/+) and B-0 -> D-+/-rho(-/+) decays in approximately 232x10(6) Upsilon(4S)-> B (B) over bar events collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. From a time-dependent maximum-likelihood fit we obtain for the parameters related to the CP violation angle 2 beta+gamma: a(D pi)=-0.010 +/- 0.023 +/- 0.007, c(lep)(D pi)=-0.033 +/- 0.042 +/- 0.012, a(D*)pi=-0.040 +/- 0.023 +/- 0.010, c(lep)(D*)pi=0.049 +/- 0.042 +/- 0.015,a(D rho)=-0.024 +/- 0.031 +/- 0.009, c(lep)(D rho)=-0.098 +/- 0.055 +/- 0.018, where the first error is statistical and the second is syste…

Search for stable hadronising squarks and gluinos with the ATLAS experiment at the LHC

Hitherto unobserved long-lived massive particles with electric and/or colour charge are predicted by a range of theories which extend the Standard Model. In this Letter a search is performed at the ATLAS experiment for slow-moving charged particles produced in proton–proton collisions at 7 TeV centre-of-mass energy at the LHC, using a data-set corresponding to an integrated luminosity of 34 pb[superscript −1]. No deviations from Standard Model expectations are found. This result is interpreted in a framework of supersymmetry models in which coloured sparticles can hadronise into long-lived bound hadronic states, termed R-hadrons, and 95% CL limits are set on the production cross-sections of…

Search for diphoton events with large missing transverse energy in 7 TeV proton-proton collisions with the ATLAS detector.

A search for diphoton events with large missing transverse energy is presented. The data were collected with the ATLAS detector in proton-proton collisions at √s=7  TeV at the CERN Large Hadron Collider and correspond to an integrated luminosity of 3.1  pb−1. No excess of such events is observed above the standard model background prediction. In the context of a specific model with one universal extra dimension with compactification radius R and gravity-induced decays, values of 1/R<729  GeV are excluded at 95% C. L., providing the most sensitive limit on this model to date.

Observation ofB0Meson Decay toa1±(1260)π∓

We present a measurement of the branching fraction of the decay B-0 -> a(1)(+/-)(1260)pi(-/+) with a(1)(+/-)(1260)->pi(-/+)pi(+/-)pi(+/-). The data sample corresponds to 218x10(6) B (B) over bar pairs produced in e(+)e(-) annihilation through the Upsilon(4S) resonance. We measure the branching fraction B(B-0 -> a(1)(+/-)(1260)pi(-/+))B(a(1)(+/-)(1260)->pi(-/+)pi(+/-)pi(+/-))=(16.6 +/- 1.9 +/- 1.5)x10(-6), where the first error quoted is statistical and the second is systematic.

Search for new phenomena in final states with large jet multiplicities and missing transverse momentum at s√=8 TeV proton-proton collisions using the ATLAS experiment

A search is presented for new particles decaying to large numbers (7 or more) of jets, with missing transverse momentum and no isolated electrons or muons. This analysis uses 20.3 fb[superscript −1] of pp collision data at s√ = 8 TeV collected by the ATLAS experiment at the Large Hadron Collider. The sensitivity of the search is enhanced by considering the number of b-tagged jets and the scalar sum of masses of large-radius jets in an event. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of various simplified supersymmetry-inspired models where gluinos are pair produced, as well as an mSUGRA/CMSSM model.

Measurement of the inelastic proton-proton cross-section at √s = 7 TeV with the ATLAS detector

The dependence of the rate of proton–proton interactions on the centre-of-mass collision energy, √s, is of fundamental importance for both hadron collider physics and particle astrophysics. The dependence cannot yet be calculated from first principles; therefore, experimental measurements are needed. Here we present the first measurement of the inelastic proton–proton interaction cross-section at a centre-of-mass energy, √s, of 7 TeV using the ATLAS detector at the Large Hadron Collider. Events are selected by requiring hits on scintillation counters mounted in the forward region of the detector. An inelastic cross-section of 60.3±2.1 mb is measured for ξ>5×10[superscript −6], where ξ is ca…

Observation ofB+→K¯0K+andB0→K0K¯0

The authors report observations of the b {yields} d penguin-dominated decays B{sup +} {yields} {bar K}{sup 0}K{sup +} and B{sup 0} {yields} K{sup 0}{bar K}{sup 0} in approximately 350 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector. They measure the branching fractions {Beta}(B{sup +} {yields} {bar K}{sup 0}K{sup +}) = (1.61 {+-} 0.44 {+-} 0.09) x 10{sup -6} and {Beta}(B{sup 0} {yields} K{sup 0}{bar K}{sup 0}) = (1.08 {+-} 0.28 {+-} 0.11) x 10{sup -6}, and the CP-violating charge asymmetry {Alpha}{sub CP} ({bar K}{sup 0} K{sup +}) = 0.10 {+-} 0.26 {+-} 0.03. Using a vertexing technique previously employed in several analyses of all-neutral final states conta…

Measurements of Partial Branching Fractions forB¯→Xulν¯and Determination of|Vub|

We present partial branching fractions for inclusive charmless semileptonic B decays (B) over bar -> X(u)l (nu) over bar, and the determination of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-ub vertical bar. The analysis is based on a sample of 383 x 10(6) gamma(4S) decays into B (B) over bar pairs collected with the BABAR detector at the SLAC PEP-II e(+)e(-) storage rings. We select events using the invariant mass M-X of the hadronic system, the invariant mass squared, q(2), of the lepton and neutrino pair, the kinematic variable P+, or one of their combinations. We then determine partial branching fractions in limited regions of phase space: Delta B = (1.18 +/- 0.09(stat) …

Search for the decayB+→Ks0Ks0π+

We search for charmless decays of charged B mesons to the three-body final state (KSKS0)-K-0 pi(+). Using a data sample of 423.7 fb(-1) collected at the Gamma(4S) resonance with the BABAR detector, corresponding to (465.1 +/- 5.1) x 10(6) (B) over bar B pairs, we find no significant signal and determine a 90% confidence level upper limit on the branching fraction of 5.1 x 10(-7).

Search for decays ofB0mesons intoe+e−,μ+μ−ande±μ∓final states

We present a search for the decays B0→e+e-, B0→μ+μ-, and B0→e±μ using data collected with the BABAR detector at the PEP-II e+e- collider at SLAC. Using a data set corresponding to 384×106 BB pairs, we do not find evidence of any of the three decay modes. We obtain upper limit on the branching fractions, at 90% confidence level, of B(B0→e+e-)<11.3×10-8, B(B0→μ+μ-)<5.2×10-8, and B(B0→e±μ)<9.2×10-8. © 2008 The American Physical Society.

Measurement of theCP-violating asymmetries inB0→Ks0π0and of the branching fractionB0→K0π0

We present a measurement of the time-dependent CP-violating asymmetries in B-0 -> K-S(0)pi(0) decays based on 383x10(6) Upsilon(4S)-> B (B) over bar events collected by the BABAR experiment at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. We measure the direct CP-violating asymmetry C-KS(0)pi(0)=0.24 +/- 0.15 +/- 0.03 and the CP-violating asymmetry in the interference between mixing and decay S-KS(0)pi(0)=0.40 +/- 0.23 +/- 0.03, where the first errors are statistical and the second are systematic. On the same sample, we measure the decay branching fraction, obtaining B(B-0 -> K-0 pi(0))=(10.3 +/- 0.7 +/- 0.6)x10(-6).

Search for a charged partner of theX(3872)in theBmeson decayB→X−K,X−→J/ψπ−π0

We search for a charged partner of the X(3872) in the decay B --> X- K, X- --> J/psi pi- pi0, using 234 million BBbar events collected at the Y(4S) resonance with the BaBar detector at the PEP-II e+e- asymmetric-energy storage ring. The resulting product branching fraction upper limits are BR(B0 --> X- K+, X- --> J/psi pi- pi0) X- K0bar,X- --> J/psi pi- pi0) < 22 x 10(-6) at the 90% confidence level.

Observation ofB→η′K*and Evidence forB+→η′ρ+

We present an observation of B-->eta'K*. The data sample corresponds to 232x10(6) BB[over ] pairs collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the Stanford Linear Accelerator Center. We measure the branching fractions (in units of 10(-6)) B(B(0)-->eta'K*0)=3.8+/-1.1+/-0.5 and B(B+-->eta'K*+)=4.9(1.7)(+1.9)+/-0.8, where the first error is statistical and the second systematic. A simultaneous fit results in the observation of B-->eta'K* with B(B-->eta'K*)=4.1(-0.9)(+1.0)+/-0.5. We also search for B-->eta'rho and eta'f(0)(980)(f(0)-->pi+pi-) with results and 90% confidence level upper limits B(B+-->eta'rho+)=8.7(-2.8-1.3)(+3.1+2.3) ( eta'rho0) eta'f(0)(980)(f(…