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+-.

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.

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.

Measurements of the Mass and Width of theηcMeson and of anηc(2S)Candidate

The mass m(eta(c)) and total width Gamma(eta(c))(tot) of the eta(c) meson have been measured in two-photon interactions at the SLAC e(+)e(-) asymmetric B Factory with the BABAR detector. With a sample of approximately 2500 reconstructed eta(c)-->K(0)(S)K+/-pi(-/+) decays in 88 fb(-1) of data, the results are m(eta(c))=2982.5+/-1.1(stat)+/-0.9(syst) MeV/c(2) and Gamma(eta(c))(tot)=34.3+/-2.3(stat)+/-0.9(syst) MeV/c(2). Using the same decay mode, a second resonance with 112+/-24 events is observed with a mass of 3630.8+/-3.4(stat)+/-1.0(syst) MeV/c(2) and width of 17.0+/-8.3(stat)+/-2.5(syst) MeV/c(2). This observation is consistent with expectations for the eta(c)(2S) state.

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 for composite and exotic fermions at LEP 2

A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed correspond to an integrated luminosity of about 48~pb$^{-1}$ at an $e^+e^-$ centre-of-mass energy of 183~GeV and about 20~pb$^{-1}$ equally shared between the centre-of-mass energies of 172~GeV and 161~GeV. The search for pair-produced new leptons establishes 95\% confidence level mass limits in the region between 70~GeV/$c^2$ and 90~GeV/$c^2$, depending on the channel. The search for singly produced excited leptons and quarks establishes upper limits on the ratio of the coupling of the excited fermio…

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.

Erratum: Measurement of the absolute branching fractions forDs−→ℓ−ν¯ℓand extraction of the decay constantfDs[Phys. Rev. D82, 091103(R) (2010)]

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…

Identified particles in quark and gluon jets

A sample of about 1.4 million hadronic Z decays, selected among the data recorded by the DELPHI detector at LEP during 1994, was used to measure for the first time the momentum spectra of K+, K-0, p, Lambda and their antiparticles in gluon and quark jets. As observed for inclusive charged particles, the production spectra of identified particles were found to be softer in gluon jets than in quark jets, with a higher total multiplicity. (C) 1997 Published by Elsevier Science B.V.

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.

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 …

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…

Search for Z0 decays to two leptons and a charged particle-antiparticle pair

Based on a sample equivalent to 365 000 hadronic Z0 decays, the search in DELPHI data for pairs of leptons accompanied by a pair of charged particles is described. A total of 11 events were found in the electron channel, 9 in the muon channel and 7 in the tau channel. Results on lepton pairs with a radiated photon are also presented. The data from all channels are compatible with the expectations from standard processes. However, one event was found in the tau channel with an unusually high mass of the charged particle pair.

Updated precision measurement of the average lifetime of B hadrons

The measurement of the average lifetime of B hadrons using inclusively reconstructed secondary vertices has been updated using both an improved processing of previous data and additional statistics from new data. This has reduced the statistical and systematic uncertainties and gives \tau_{\mathrm{B}} = 1.582 \pm 0.011\ \mathrm{(stat.)} \pm 0.027\ \mathrm{(syst.)}\ \mathrm{ps.} Combining this result with the previous result based on charged particle impact parameter distributions yields \tau_{\mathrm{B}} = 1.575 \pm 0.010\ \mathrm{(stat.)} \pm 0.026\ \mathrm{(syst.)}\ \mathrm{ps.}

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.

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 Time-DependentCPAsymmetry in NeutralBDecays toJ/ψπ0

We present the first study of the time-dependent CP-violating asymmetry in B0-->J/psi pi(0) decays using e(+)e(-) annihilation data collected with the BABAR detector at the Upsilon(4S) resonance during the years 1999-2002 at the PEP-II asymmetric-energy B Factory at SLAC. Using approximately 88 x 10(6) BB; pairs, our results for the coefficients of the cosine and sine terms of the CP asymmetry are C(J/psi pi(0))=0.38+/-0.41(stat)+/-0.09(syst) and S(J/psi pi(0))=0.05+/-0.49(stat)+/-0.16(syst).

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 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.

Production of strange particles in the hadronic decays of the Z0

Abstract An analysis of the production of strange particles from the decays of the Z 0 boson into multihadronic final states is presented. The analysis is based on about 90 000 selected hadronic Z 0 decays collected by the DELPHI detector at LEP in 1990. K s 0 , K ∗± , Λ( Λ ) and Ξ − ( Ξ + ) have been identified by their characteristic decays. The measured production cross sections are compared with predictions of the Lund Monte Carlo tuned to data at PEP/PETRA energies.

Improved measurements of cross sections and asymmetries at the Z0 resonance

During the 1992 running period of the LEP e+e- collider, the DELPHI experiment accumulated approximately 24 pb-1 of data at the Z0 peak. The decays into hadrons and charged leptons have been analysed to give values for the cross sections and leptonic forward-backward asymmetries which are significantly improved with respect to those previously published by the DELPHI collaboration. Incorporating these new data, more precise values for the Z0 resonance parameters are obtained from model-independent fits. The results are interpreted within the framework of the Standard Model, yielding for the top quark mass m(t) = 157(-48)+36(expt.)-20(+19)(Higgs) GeV, and for the effective mixing angle sin2 …

Search forfJ(2220)in RadiativeJ/ψDecays

We present a search for f_(J)(2220) production in radiative J/ψ→γf_(J)(2220) decays using 460  fb^(-1) of data collected with the BABAR detector at the SLAC PEP-II e^(+)e^(-) collider. The f_(J)(2220) is searched for in the decays to K^(+)K^(-) and K_(S)^(0)K_(S)^(0). No evidence of this resonance is observed, and 90% confidence level upper limits on the product of the branching fractions for J/ψ→γf_(J)(2220) and f_(J)(2220)→K^(+)K^(-)(K_(S)^(0)K_(S)^(0)) as a function of spin and helicity are set at the level of 10^(-5), below the central values reported by the Mark III experiment.

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 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.

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 for neutral heavy leptons produced in Z decays

Weak isosinglet Neutral Heavy Leptons ($\nu_m$) have been searched for using data collected by the DELPHI detector corresponding to $3.3\times 10^{6}$ hadronic~Z$^{0}$ decays at LEP1. Four separate searches have been performed, for short-lived $\nu_m$ production giving monojet or acollinear jet topologies, and for long-lived $\nu_m$ giving detectable secondary vertices or calorimeter clusters. No indication of the existence of these particles has been found, leading to an upper limit for the branching ratio $BR($Z$^0\rightarrow \nu_m \overline{\nu})$ of about $1.3\times10^{-6}$ at 95\% confidence level for $\nu_m$ masses between 3.5 and 50 GeV/$c^2$. Outside this range the limit weakens rap…

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…

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 of theB0→π−ℓ+νandB+→η(′)ℓ+νbranching fractions, theB0→π−ℓ+νandB+→ηℓ+νform-factor shapes, and determination of|Vub|

We report the results of a study of the exclusive charmless semileptonic decays, B^+ → η^((′))l^+ν and B^0 → π^-l^+ν, undertaken with approximately 464 × 10^6 BB pairs collected at the Υ(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with a loose neutrino reconstruction technique. We obtain partial branching fractions for B^+ → ηl^+ν and B^0 → π^-l^+ν decays in three and 12 bins of q^2, respectively, from which we extract the f_+(q^2) form-factor shapes and the total branching fractions B(B^+ → ηl^+ν)=(0.36 ± 0.05_(stat) ± 0.04_(syst))× 10^(-4) and B(B^0 → π^-l^+ν)=(1.42 ± 0.05_(stat) ± 0.07_(syst)) × 10^(-4). We also measure B…

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.

Measurement of the forward-backward asymmetry of e(+)e(-)-]z-]b(b)over-bar using prompt leptons and a lifetime tag

The forward-backward asymmetry of the process e+e-→Z→b {Mathematical expression} has been measured using events collected by the DELPHI experiment during the 1991 and 1992 LEP runs. This data sample corresponded to 884 000 hadronic Z decays at a centre-of-mass energy {Mathematical expression}. The tagging of b-quark events was performed using two approaches; the first was based on the semileptonic decay channels b→X+μ and b→X+e, the second used a lifetime tag with jet-charge reconstruction. The results of these two methods were combined to give {Mathematical expression} With the semileptonic sample, the forward-backward asymmetry of the process e+e-→Z→ {Mathematical expression} was also mea…

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 lifetime of tau-lepton

The tau lepton lifetime is measured with the L3 detector at LEP using the complete data taken at centre-of-mass energies around the Z pole resulting in tau_tau = 293.2 +/- 2.0 (stat) +/- 1.5 (syst) fs. The comparison of this result with the muon lifetime supports lepton universality of the weak charged current at the level of six per mille. Assuming lepton universality, the value of the strong coupling constant, alpha_s is found to be alpha_s(m_tau^2) = 0.319 +/- 0.015(exp.) +/- 0.014 (theory). The tau lepton lifetime is measured with the L3 detector at LEP using the complete data taken at centre-of-mass energies around the Z pole resulting in τ τ =293.2 ± 2.0 (stat) ± 1.5 (syst) fs . The c…

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.

Rapidity correlations in Lambda baryon and proton production in hadronic Z0 decays

In an analysis of multihadronic events recorded at LEP by DELPHI in the years 1992 through 1994, charged hadrons are identified using the measurement of their energy loss and their Cherenkov angle. Rapidity correlations of \La-\La, proton-proton, and \La-proton pairs are compared. The agreement with the string and cluster fragmentation models is tested. For those pairs that frame a meson in terms of rapidity the compensation of strangeness is studied. For \La{}$\overline{\mathrm{p}}$ pairs the additional correlation with respect to charged kaons is analysed.

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 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…

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 trilinear gauge couplings in e(+)e(-) collisions at 161 GeV and 172 GeV

Trilinear gauge boson couplings are measured using data taken by DELPHI at 161 GeV and 172 GeV, Values for WWV couplings (V = Z,gamma) are determined from a study of the reactions e(+)e(-) --> W+W- and e(+)e(-) --> We nu, using differential distributions from the WW final state in which one W decays hadronically and the other leptonically, and total cross,section data from other channels, Limits are also derived on neutral ZV gamma couplings from an analysis of the reaction e(+)e(-) --> gamma + invisible particles. (C) 1998 Elsevier Science B.V.

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.

Search for neutralino pair production at root s = 189 GeV

A search for pair-production of neutralinos at a LEP centre-of-mass energy of 189 GeV gave no evidence for a signal. This limits the neutralino production cross-section and excludes regions in the parameter space of the Minimal Supersymmetric Standard Model (MSSM).

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.

A search for neutral higgs particles in Z$^0$ decays

Abstract The search in DELPHI data for neutral Higgs bosons is described. No candidate for the Standard Model Higgs is seen in Z0 decays to H 0 ν ν , H 0 μ + μ − or H0τ+τ− after selections that proved efficient for finding simulated H0. One remaining candidate for Z0 → H0e+e− is consistent with background. Together with our earlier studies, these results restrict the H0 mass to be above 38 GeV/c2 at the 95% confidence level. No signal is found for decays of Minimal Supersymmetric Standard Model neutral Higgs bosons to τ+τ−. Limits are obtained for their decays to produce four jets.

Search for the t and b' quarks in hadronic decays of the Z0 boson

We present a search for the third generation up type quark t and a possible fourth down type quark b' in hadronic Z0 decays observed in DELPHI at the LEP collider. For any scenario with a decay through the charged current or into a charged Higgs with a mass at least 6 GeV/c2 below the t and 3 GeVc2 below the b' mass, we set a lower limit for the t quark mass at 44.0 GeV/c2 and for the b' mass at 44.5 GeV/c2. For specific scenarios the mass limits are slightly higher, e.g. for charged current decays the limits are 44.5 and 45.0 GeV/c2 respectively, where all limits are given at a 95% confidence level. © 1990.

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…

Measurements of Branching Fractions andCP-Violating Asymmetries inBMeson Decays to Charmless Two-Body States Containing aK0

We present measurements of branching fractions and \CP-violating asymmetries in decays of $B$ mesons to two-body final states containing a \Kz. The results are based on a data sample of approximately 88 million \upsbb decays collected with the \babar detector at the \pep2 asymmetric-energy $B$ Factory at SLAC. We measure $\BR(\Bp\to\Kz\pip) = (22.3 \pm 1.7 \pm 1.1)\times 10^{-6}$, $\BR(\Bz\to\Kz\piz) = (11.4\pm 1.7\pm 0.8)\times 10^{-6}$, $\BR(\Bp\to\Kzb\Kp) < 2.5\times 10^{-6}$, and $\BR(\Bz\to\KzKzb) < 1.8\times 10^{-6}$, where the first uncertainty is statistical and the second is systematic, and the upper limits are at the 90% confidence level. In addition, the following \CP-violating a…

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…

Observation of a Significant Excess ofπ0π0Events inBMeson Decays

We present a study of the decay B0 -> p0p0 based on a sample of 124 * 106 B.hivin.B pairs recorded by the BABAR detector at the PEP-II asym.-energy B Factory at SLAC. We observe 46 +- 13 +- 3 events, where the first error is statistical and the second is systematic, corresponding to a significance of 4.2 std. deviations including systematic uncertainties. We measure the branching fraction B(B0 -> p0p0) = (2.1 +- 0.6 +- 0.3) * 10-6, averaged over B0 and .hivin.B0 decays. [on SciFinder (R)]

PRODUCTION CHARACTERISTICS OF K-0 AND LIGHT MESON RESONANCES IN HADRONIC DECAYS OF THE Z(0)

An analysis of inclusive production of K0and the meson resonances K*±(892), ρ0(770), f0(975) and f2(1270) in hadronic decays of the Z0is presented, based on about 973,000 multihadronic events collected by the DELPHI detector at LEP during 1991 and 1992. Overall multiplicities have been determined as 1.962±0.060 K0mesons, 0.712±0.067 K*±(892) and 1.21±0.15ρ0(770) per hadronic Z0decay. The average multiplicities of f0(975) for scaled momentum, xp, in the range 0.05≤xp≤0.6 and of f2(1270) for 0.05≤xp≤1.0 are 0.098±0.016 and 0.170±0.043 respectively. The f0(975) and ρ0(770)xp-spectra have similar shapes. The f2(1270)/ρ0(770) ratio increases with xp. The average multiplicities…

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…

Performance of the DELPHI detector

DELPHI (DEtector with Lepton, Photon and Hadron Identification) is a detector for e(+)e(-) physics, designed to provide high granularity over a 4 pi solid angle, allowing an effective particle identification, It has been operating at the LEP (Large Electron-Positron) collider at CERN since 1989. This article reviews its performance.

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)+…

Evidence for B$^{0}_{s}$ meson production in Z$^0$ decays

Seven unambiguous events out of a sample of 270 000 Z0 decays, contain in tile same jet a D(s) meson and a muon at large transverse momentum relative to the et axis. These events are direct evidence for B(s)0 meson production in hadronic Z0 decays. The production rate of these events, relative to all hadronic Z0 decays is ( 18 +/- 8) x 10(-5) this number including the relevant branching fractions of the B(s)0 and D(s). The value of the B(s)0 meson lifetime relative to the average B meson lifetime is measured to be 0.8 +/- 0.4.

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.

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}.

Measurement of the Inclusive Charmless Semileptonic Branching Ratio ofBMesons and Determination of|Vub|

We report a measurement of the inclusive charmless semileptonic branching fraction of B mesons in a sample of 89 x 10(6) (-)BB events recorded with the BABAR detector at the Upsilon(4S) resonance. 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. The number of signal events is extracted from the mass distribution of the hadronic system accompanying the lepton and is used to determine the ratio of branching fractions B((-)B-->X(u)lnu;)/B((-)B-->Xlnu;)=[2.06+/-0.25(stat)+/-0.23(syst)+/-0.36(theo)]x10(-2). Using the measured branching fraction for inclusive semileptonic B decays, we find B((-)B-->X(u)lnu;)…

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 $\Dz\to e^\pm\mu^\mp$.

Observation of the DecayB→J/ψηKand Search forX(3872)→J/ψη

We report the observation of the B meson decay B±→J/ψηK± and evidence for the decay B0→J/ψηKS0, using 90×106 BB events collected at the Υ(4S) resonance with the BABAR detector at the SLAC PEP-II e+e- asymmetric-energy storage ring. We obtain branching fractions of B(B±→J/ψηK±)=[10.8±2.3(stat)±2.4(syst)]×10-5 and B(B0→J/ψηKS0)=[8.4±2.6(stat)±2.7(syst)]×10-5. We search for the new narrow mass state, the X(3872), recently reported by the Belle Collaboration, in the decay B±→X(3872)K±,X(3872)→J/ψη and determine an upper limit of B[B±→X(3872)K±→J/ψηK±]<7.7×10-6 at 90% confidence level.

Observation of orbitally excited B mesons

Experimental evidence for the existence of orbitally excited B meson states is presented in an analysis of the Bπ and B*π distribution of Q = m(B**) - m(B(*)) - m(π) using Z0decay data taken with the DELPHI detector at LEP. The mean Q-value of the decays B**→ B(*)π is measured to be 284 ± 5 (stat.) ± 15 (syst.) MeV/c2, and the Gaussian width of the signal is 79 ± 5 (stat.) ± 8 (syst.) MeV/c2. This signal can be described as a single resonance of mass m = 5732 ± 5 (stat.) ± 20 (syst.) MeV/c2and full width Γ = 145 ± 28 MeV/c2. The observed shape is also consistent with the production of several broad and narrow states as predicted by the quark model and partly observed in the D-…

Measurement of the branching fraction forB±→χc0K±

We present a measurement of the branching fraction of the decay ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c0}{K}^{\ifmmode\pm\else\textpm\fi{}}$ from a sample of $89\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. The ${\ensuremath{\chi}}_{c0}$ meson is reconstructed through its two-body decays to ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${K}^{+}{K}^{\ensuremath{-}}.$ We measure $\mathcal{B}{(B}^{\ifmmode\pm\else\textpm\fi{}}\stackrel{\ensuremath{\rightarrow}}{}{\ensuremath{\chi}}_{c0}{K}^{\ifmmode\pm\else\textpm\fi{}})\ifmmode\times\e…

A Search for Sleptons and Gauginos in Z0 Decays

Using a data sample corresponding to 10 000 hadronic Z0 decays, we have searched for the production of sleptons and gauginos in the two-prong decays of Z0. No candidate remains after straightforward selections. For neutralinos, we use selection methods developed in our previous search for neutral Higgs particles. The negative results are translated into improved mass limits and parameter constraints on the minimal supersymmetric extension of the standard model.

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 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.

Search for exclusive decays of the Lambda_b baryon and measurement of its mass

A search for fully reconstructed \lb beauty baryons is performed using about 3 million Z decays collected with the DELPHI detector at LEP. The analysis relies on the combined use of the accurate tracking and of the hadron identification capabilities of DELPHI. A total of four events has been found, three in the \lc\ppm channel and one in the \lc\a1m channel over a small background. The \lb beauty baryon mass is measured to be (~ 5668 \pm 16~ ({\rm stat.}) \pm 8~({\rm syst.})~)~ \mv.

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.

Tuning and test of fragmentation models based on identified particles and precision event shape data

Event shape and charged particle inclusive distributions are measured using 750000 decays of the $Z$ to hadrons from the DELPHI detector at LEP. These precise data allow a decisive confrontation with models of the hadronization process. Improved tunings of the JETSET ARIADNE and HERWIG parton shower models and the JETSET matrix element model are obtained by fitting the models to these DELPHI data as well as to identified particle distributions from all LEP experiments. The description of the data distributions by the models is critically reviewed with special importance attributed to identified particles.

Evidence forB+→J/ψpΛ¯and Search forB0→J/ψpp¯

We have performed a search for the decays ${B}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}p\overline{\ensuremath{\Lambda}}$ and ${B}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}p\overline{p}$ in a data set of $(88.9\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\ensuremath{\Upsilon}(4S)$ decays collected by the BABAR experiment at the PEP-II ${e}^{+}{e}^{\ensuremath{-}}$ storage ring at the Stanford Linear Accelerator Center. Four charged $B$ candidates have been observed with an expected background of $0.21\ifmmode\pm\else\textpm\fi{}0.14$ events. The corresponding branching fraction is $({12}_{\ensuremath{-}6}^{+9})\ifmmode\times\else\texttimes\fi{}{10}^…

Measurement and interpretation of the $W$-pair cross-section in $e^+e^-$ interactions at 161 GeV

In 1996 LEP ran at a centre-of-mass energy of 161~GeV, just above the threshold of W-pair production. DELPHI accumulated data corresponding to an integrated luminosity of $9.93 {\mathrm{~pb^{-1}}}$, and observed 29 events that are considered as candidates for W-pair production. From these, a cross-section for the doubly resonant $e^+e^-\to\mathrm{WW}$ process of $3.67~^{+0.97}_{-0.85} \pm 0.19{\mathrm{~pb}}$ has been measured. Within the Standard Model, this cross-section corresponds to a mass of the W-boson of ${\mathrm{80.40~\pm~0.44~(stat.)~\pm~0.09~(syst.) ~\pm 0.03~(LEP)~GeV}}/c^2$. Alternatively, if $m_{\mathrm{W}}$ is held fixed at its current value determined by other experiments, t…

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 Production of Invisible Final States in Single-Photon Decays of Υ(1S)

We search for single-photon decays of the Upsilon(1S) resonance, Upsilon-&gt;gamma+invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A0, or a pair of dark matter particles, chi chi-bar. Both A0 and chi are assumed to have zero spin. We tag Upsilon(1S) decays with a dipion transition Upsilon(2S)-&gt;pi+pi-Upsilon(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range m_A0&lt;=9.2 GeV and m_chi&lt;=4.5 GeV in the sample of 98e6 Upsilon(2S) decays collected with the BaBar detector and set stringent limits on new physics models that contain light dark ma…

Search for heavy charged scalars in Z$^0$ Decays

Using a sample of Z0's corresponding to about 12 000 events, we have searched for the production of charged scalars, primarily charged Higgs particles, decaying into c̄scs̄, τν+jets, and τντν. The average detection efficiency is 20%. No candidate was found in the leptonic modes. Masses in the range up to 30-36 GeV/c2 are excluded, extending the mass domain covered by previous e+e- machines.

A search for $\eta'_c$ production in photon-photon fusion at LEP

A search for the production of the $\eta'_c$ meson, the first radial excitation of the ground state of charmonium $\eta_c$(2980), in the photon-photon fusion reaction at LEP has been performed using the data collected by the DELPHI detector during 1992-1996. No evidence of $\eta'_c$ production is found in the mass region 3520--3800 MeV/c^2. An upper limit for the ratio of the two-photon widths of the $\eta'_c$ and $\eta_c$ is obtained.

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.

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).

Search for the Radiative DecaysB→ργandB0→ωγ

A search for the exclusive radiative decays B {yields} {rho}(770){gamma} and B{sup 0} {yields} {omega}(782){gamma} is performed on a sample of about 84 million B{bar B} events collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. No significant signal is seen in any of the channels. We set upper limits on the branching fractions {Beta} of {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) < 1.2 x 10{sup -6}, {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) < 2.1 x 10{sup -6}, and {Beta}(B{sup 0} {yields} {omega}{gamma}) < 1.0 x 10{sup -6} at 90% confidence level (C.L.). Using the assumption that {Lambda}(B {yields} {rho}{gamma}) = {Lambda}(B{sup +} {yields} …

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…

Measurements of the tau polarisation in Z0 decays

A sample of Z0→τ+τ- events observed in the DELPHI detector at LEP in 1991 and 1992 is analysed to measure the τ polarisation in the exclusive decay channels {Mathematical expression}, {Mathematical expression}, πν, ρν and a1ν. The τ polarisation is also measured with an inclusive hadronic analysis which benefits from a higher efficiency and a better systematic precision than the use of the exclusive decay modes. The results have been combined with those published on the 1990 data. A measurement of the τ polarisation as a function of production angle yields the values for the mean τ polarisation 〈P〉τ=-0.148±0.022 and for the Z0 polarisation PZ=-0.136±0.027. These results are used to determin…

A Measurement of the Bbbar Forward-backward Asymmetry Using the Semileptonic Decay Into Muons

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).

Branching fraction measurements ofB→ηcKdecays

We study the decays B{sup +} {yields} {eta}{sub c}K{sup +} and B{sup 0} {yields} {eta}{sub c}K{sup 0}, where the {eta}{sub c} is reconstructed in the K{sub S}{sup 0} K{sup {+-}} {pi}{sup {-+}} and K{sup +}K{sup -} {pi}{sup 0} decay modes. Results are based on a sample of 86 million B{bar B} pairs collected with the BABAR detector at the SLAC e{sup +}e{sup -} B Factory. We measure the branching fractions {Beta}(B{sup +} {yields} {eta}{sub c}K{sup +}) = (1.34 {+-} 0.09 {+-} 0.13 {+-} 0.41) x 10{sup -3} and {Beta}(B{sup 0} {yields} {eta}{sub c}K{sup 0}) = (1.18 {+-} 0.16 {+-} 0.13 {+-} 0.37) x 10{sup -3}, where the first error is statistical, the second is systematic, and the third reflects th…

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…

J / psi production in the hadronic decays of the Z.

Abstract: J/psi mesons have been reconstructed from their decay to mu(+)mu(-) and e(+)e(-), using the data collected by the DELPHI experiment during 1991 and 1992 at the LEP collider. From about 1 million hadronic Z decays 153 +/- 17 J/psi were found, 5.4 +/- 2.3 psi' were obtained in the channel J/psi(--> mu(+)mu(-))pi(+)pi(-) and 6.4 +/- 2.7 chi(c) in the channel J/psi(--> mu(+)mu(-))gamma. As the dominant source of J/psi mesons is from b quarks, the following branching ratios: Br(b-->J/psi X) = (1.12 +/- 0.12 (stat.) +/- 0.10 (syst.))%, Br(b --> psi' X) = (0.48 +/- 0.22 (stat.) +/- 0.10 (syst.))%, Br(b-->chi(cl) X) = (1.4 +/- 0.6 (stat.)(-0.2)(+0.4) (syst.))% were measured. From the prop…

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 …

Search for exclusive charmless b meson decays with the Delphi detector at Lep

Charmless hadronic decays of beauty mesons have been searched for using the data collected with the DELPHI detector at the LEP collider. Several two, three and four-body decay modes have been investigated. Particle identification was used to distinguish the final states with protons, kaons and pions. Three candidate events selected in two-body decay modes are interpreted as evidence for charmless B decays. No excess has been found in higher multiplicity modes and improved upper limits for some of the branching ratios are given. © 1995.

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…

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.

A Precise Measurement of the $\tau$ Polarisation at LEP-1

The $\tau$ polarisation has been studied with the ${\rm e^+e^-}\to \tau^+\tau^-$ data collected by the DELPHI detector at LEP in 1993, 1994 and 1995 around the Z resonance firstly through the exclusive decay channels ${\rm e}\nu\bar{\nu}$ , $\mu\nu\bar{\nu}$ , $\pi\nu$ , $\rho\nu$ and ${\rm a}_1\nu$ and secondly with an inclusive hadronic analysis which benefits from a higher efficiency and a better systematic precision. The results have been combined with those previously published on 1990 to 1992 DELPHI data, to produce results which reflect the full LEP-1 statistics. The fit of the $\tau$ polarisation dependence on the production angle yielded the polarisation parameters ${\cal A}_{_{\sc…

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 inclusive production of light meson resonances in hadronic decays of the Z0

A study of inclusive production of the meson resonances ρ0, K*0 (892), f{hook}0 (975) and f{hook}2 (1270) in hadronic decays of the Z0 is presented. The measured mean meson multiplicity per hadronic event is 0.83 ± 0.14 for the ρ0 0.64 ± 0.24 for the K*0 (892), 0.10 ± 0.04 for the f{hook}0 (975) in the momentum range p &gt; 0.05pbeam (xp &gt; 0.05) and 0.11 ± 0.05 for the f{hook}2 (1270) for xp &gt; 0.1. These values and the corresponding differential cross sections ( 1 σhadr) dσ dxp for the vector mesons are in good agreement with the predictions of the JETSET 7.3 PS and HERWIG 5.4 models. The f{hook}2 (1270) production is overestimated by HERWIG but its xp-shape is correctly reproduced. T…

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 …

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…

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.

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…

Identified charged particles in quark and gluon jets

A sample of 2.2 million hadronic Z decays, selected from the data recorded by the Delphi detector at LEP during 1994-1995 was used for an improved measurement of inclusive distributions of pi+, K+ and p and their antiparticles in gluon and quark jets. The production spectra of the individual identified particles were found to be softer in gluon jets compared to quark jets, with a higher multiplicity in gluon jets as observed for inclusive charged particles. A significant proton enhancement in gluon jets is observed indicating that baryon production proceeds directly from colour objects. The maxima, xi^*, of the xi-distributions for kaons in gluon and quark jets are observed to be different.

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 inclusive K*(0)(892), phi(1020) and K-2*(0)(1430) production in hadronic Z decays

The inclusive production of the neutral vector mesons K-*0(892) and phi(1020), and of the tensor meson K-2(*0)(1430), in hadronic decays of the Z has been mea sured by the DELPHI detector at LEP. The average production rates per hadronic Z decay have been determined to be 0.77 +/- 0.08 K-2(*0)(892), 0.104 +/- 0.008 phi(1020) and 0.079 +/- 0.040 K-2(*0)(1430). The ratio of the tensor-to-vector meson production yields, [K-2(*0)(1430)]/[K-*0(892)] = 0.10 +/- 0.05, is smaller than the [f(2)(1270)]/[rho(0)(770)] and [f'(2)(1525)]/[phi(1020)] ratios measured by DELPHI. The production rates and differential cross sections are compared with the predictions of JETSET 7.4 tuned to the DELPHI data and…

Measurement of the inclusive charmless and double-charm B branching ratios

The DELPHI experiment at LEP has measured the inclusive charmless B hadron decay branching ratio, the B branching ratio into two charmed particles, and the total number of charmed particles per B decay, using the hadronic Z data taken between 1992 and 1995. The results are extracted from a fit to the b-tagging probability distribution based on the precise impact parameter measurements made using the microvertex detector. The inclusive charmless B branching ratio, including B decays into hidden charm (c (c) over bar), is measured to be 0.033 +/- 0.021. The B branching ratio into two open charmed particles is 0.136 +/- 0.042. The mean number of charmed particles per B decay (including hidden …

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…

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 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}{…

First evidence for a charm radial excitation, D

Using D*+ mesons exclusively reconstructed in the DELPHI detector at LEP, an excess of 66 +/- 14(stat.) events is observed in the D(*+)pi(+)pi(-) final state with a mass of 2637 +/- 2(stat.) +/- 6(syst.) MeV/c(2) and a full width smaller than 15 MeV/c(2) (95% C.L.). This signal is compatible with the expected decay of a radially excited D*' (J(P) = 1(-))meson. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

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 …

A comparison of jet production rates on the Z0 resonance to perturbative QCD

The production rates for 2-, 3-, 4- and 5-jet hadronic final states have been measured with the DELPHI detector at the e+e- storage ring LEP at centre of mass energies around 91.5 GeV. Fully corrected data are compared to O(αs 2) QCD matrix element calculations and the QCD scale parameter ΛMS is determined for different parametrizations of the renormalization scale μ2. Including all uncertainties our result is αs(MZ 2)=0.114±0.003[stat.]±0.004[syst.]±0.012[theor.] .

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 $|V_{td}/V_{ts}|=0.177\pm 0.043$.

Search for pair production of heavy objects in 4-jet events at sqrt {s}$=130-136 GeV

Results are presented of a search for pair production of heavy objects decaying into four hadronic jets, as expected for example from associated or pair production of MSSM Higgs bosons, hA or H$^+$H$^-$, using a data sample of $5.9\,$pb$^{-1}$ of $e^+ e^-$ collisions at $\sqrt{s}=130$-$136\,{\mathrm {GeV}}$ collected with the DELPHI detector at LEP in November 1995. The data and expectations from standard processes agree after four-jet selections. An analysis based on $b$-tagging finds no hA candidate with high mass. A study optimized to search for H$^+$H$^-$ events with mass in the 40-50$\,{\mathrm{GeV}}/c^2$ range also finds no candidate. Finally a comparison is made with a recent ALEPH a…

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.

Measurement of Branching Fractions and Charge Asymmetries inB±→ρ±π0andB±→ρ0π±Decays, and Search forB0→ρ0π0

We present measurements of branching fractions and charge asymmetries in $B$-meson decays to ${\ensuremath{\rho}}^{+}{\ensuremath{\pi}}^{0}$, ${\ensuremath{\rho}}^{0}{\ensuremath{\pi}}^{+}$, and ${\ensuremath{\rho}}^{0}{\ensuremath{\pi}}^{0}$. The data sample comprises $89\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$ decays collected with the BABAR detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. We find the charge-averaged branching fractions $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{+}{\ensuremath{\pi}}^{0})=[10.9\ifmmode\pm\else\textpm\fi{}1.9\mathrm{(}\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{…

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.

Study ofB±→J/ψπ±andB±→J/ψK±Decays: Measurement of the Ratio of Branching Fractions and Search for DirectCPViolation

Decays that measure the ratio of branching fractions and searches for direct CP violations were analyzed. The decays were collected with the BABAR detector at the PEP-II asymmetric B factory at SLAC. The fitted asymmetries for the small observed differences in the tracking efficiency were corrected between positively and negatively charged track. It was found that the uncertainty in the fixed parameters of the PDFs, determined by fits to stimulated or nonsignal data sets, contributed 0.001 to the systematic errors.

A measurement of the tau lifetime

The tau lepton lifetime is measured using four different methods with the DELPHI detector. Three measurements using one prong decays are combined, accounting for correlations, resulting in tau(tau) = 298 +/- 7 (stat.) +/- 4 (syst.) fs while the decay length distribution of three prong decays gives tau(tau) = 298 +/- 13 (stat.) +/- 5 (syst.) fs. The combined result is tau(tau) = 298 +/- 7 fs. The ratio of the Fermi coupling constant from tau decay relative to that from muon decay is found to be 0.985 +/- 0.013, compatible with lepton universality.

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→…

Energy dependence of inclusive spectra in e+ e- annihilation

Inclusive charged hadron distributions as obtained from the DELPHI measurements at 130, 136, 161, 172 and 183 GeV are presented as a function of the variables rapidity, xi(p), p and transversal momenta. Data are compared with event generators and with MLLA calculations, in order to examine the hypothesis of local parton hadron duality. The differential momentum spectra show an indication for coherence effects in the production of soft particles. The relation between the energy dependence of the charged multiplicity and the rapidity distribution is examined. (C) 1999 Elsevier Science B.V. All rights reserved.

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…

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}.

Update of the search for charginos nearly mass-degenerate with the lightest neutralino

The data collected by DELPHI in 1998 at the centre-of-mass energy of 189 GeV have been used to update the search for charginos nearly mass-degenerate with the lightest supersymmetric particle, which is assumed to be the lightest neutralino. Mass differences below \Delta M = 3 GeV/c^2 are considered. No excess of events with respect to the Standard Model expectation has been observed, and exclusions in the plane of \Delta M versus chargino mass are given. The new \Delta M independent lower limit on the mass of the chargino is 62.4 GeV/c^2 in the higgsino scenario (which includes the gaugino mass unification scenario), if all sfermions are heavier than the lightest chargino. In the approximat…

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)…

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.

Lifetime of Charged and Neutral B-hadrons Using Event Topology

The lifetimes of charged and neutral B hadrons have been measured using data collected by the DELPHI experiment at LEP between 1991 and 1993. B hadrons are tagged as jets with a secondary vertex and the charge of the B candidate is taken to be the sum of the charges of the particles in the secondary vertex. Approximately 1,434,000 multihadronic \PZz decays yielded 1817 B hadron candidates. The B purity was estimated to be around 99.1\pm0.3\%, and 83\% (70\%) of the events measured as neutral (charged) came from neutral (charged) B's. The mean lifetimes of charged and neutral B hadrons were found to be \TAUBC\pm\ERRBC\;(stat.)\pm\SYSBC\;(syst.)~ps and \TAUBN\pm\ERRBN\;(stat.)\pm\SYSBN\;(syst…

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.

Search for the sgoldstino at √s = 189 to 202 GeV.

A search for the supersymmetric partner of the goldstino, the sgoldstino S, at LEP2 is presented. The production Sgamma followed by S decay into two gluons or into two photons was studied at 189 - 202 GeV LEP centre-of-mass energies. No evidence for the S production was found and limits on the S mass corresponding to different theory parameters are given.

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 neutral and charged Higgs bosons in $e^+ e^-$ collisions at $\sqrt{s}$= 161 GeV and 172 GeV

A search for neutral and charged Higgs bosons has been performed in the data collected by the {\sc DELPHI} detector at centre-of-mass energies of 161~GeV and 172~GeV. The analysis assumes either the pair-production of charged Higgs bosons, ${\mathrm H}^{\pm}$, or the production of the lightest neutral Higgs boson, h, with either a Z or a neutral pseudoscalar Higgs boson, A. All final state topologies expected from the decay of h and A %neutral Higgs particles into hadrons or a pair of $\tau$ leptons, and from the decay of ${\mathrm H}^{\pm}$ %charged Higgs bosons into a pair of quarks or a $\tau \nu_{\tau}$ pair have been considered. %In the case of the associated production with a Z boson,…

Search for promptly produced heavy quarkonium states in hadronic Z decays

A search has been made for direct production of heavy quarkonium states in more than 3 million hadronic Z^{0} decays in the 1991-1994 DELPHI data. Prompt J/\psi, \psi(2S) and \Upsilon candidates have been searched for through their leptonic decay modes using criteria based on the kinematics and decay vertex positions. New upper limits are set at the 90 \% confidence level for {Br( Z^0 \rightarrow \left( Q \bar{Q} \right) X ) / Br( Z^0 \rightarrow \mbox{hadrons})} for various strong production mechanisms of J/\psi and \Upsilon; these range down to 0.9 \times 10^{-4}. The limits are set in the presence of a small excess (\sim 1 \% statistical probability of a background fluctuation) in the su…

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 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.

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…

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 trilinear gauge boson couplings WWV, (V Z,gamma) in e(+)e(-) collisions at 189 GeV

Measurements of the trilinear gauge boson couplings WWgamma and WWZ are presented using the data taken by DELPHI in 1998 at a centre-of-mass energy of 189 GeV and combined with DELPHI data at 183 GeV. Values are determined for Delta(g_1^Z) and Delta(kappa_gamma), the differences of the WWZ charge coupling and of the WWgamma dipole coupling from their Standard Model values, and for lambda_gamma, the WWgamma quadrupole coupling. A measurement of the magnetic dipole and electric quadrupole moment of the W is extracted from the results for Delta(kappa_gamma) and lambda_gamma. The study uses data from the final states jjlv, jjjj, lX, jjX and gammaX, where j represents a quark jet, l an identifie…

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.

A Precise Measurement of the Tau Lepton Lifetime

The tau lepton lifetime has been measured using three different methods with the DELPHI detector. Two measurements of one-prong decays are combined, accounting for correlations, giving a result of \tau_\tau = 291.8 \pm 3.3 \mbox{ (stat.)} \pm 2.0 \mbox{(sys.) fs} while the decay length distribution of three-prong decays gives the result \tau_{\tau} = 286.7 \pm 4.9 \mbox{ (stat.)} \pm 3.3 \mbox{ (sys.) fs}. Combining the results presented here with previous DELPHI measurements, we get \tau_{\tau} = 291.4 \pm 3.0 fs and find that the ratio of the coupling constant for tau decay relative to that for muon decay is 0.990 \pm 0.009, compatible with lepton universality.

A search for invisible Higgs bosons produced in e+e- interactions at LEP 2 energies

Searches for HZ production with the Higgs boson decaying into an invisible final state have been performed with the data collected by the DELPHI experiment up to the centre-of-mass energy of 183 GeV. The hadronic and muon pair final states of the Z boson were analysed. From the absence of signal, upper limits on the cross-section and the corresponding Higgs boson mass limits were set at 95% confidence level. The results are interpreted as excluded parameter regions in the framework of the minimal supersymmetric standard model and in the simplest Majoron model with one Higgs doublet and one Higgs singlet field. (C) 1999 Elsevier Science B.V. All rights reserved.

Strange baryon production in Z hadronic decays

A study of the production of strange octet and decuplet baryons in hadronic decays of the Z recorded by the DELPHI detector at LEP is presented. This includes the first measurement of the ∑± average multiplicity. The total and differential cross sections, the event topology and the baryon-antibaryon correlations are compared with current hadronization models. © 1995 Springer-Verlag.

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.

Search for chargino pair production in scenarios with gravitino LSP and stau NLSP at GeV at LEP

Promptly decaying lightest charginos were searched for in the context of scenarios with gravitino LSP. It was assumed that the stau is the next to lightest supersymmetric particle (NLSP). Data collected with the DELPHI detector at a centre-of-mass energy near 183~{~mbox{${mathrm{GeV}}$}}\nwere analysed combining the methods developed in previous searches. No evidence for the production of these particles was found. Hence, limits were derived at 95% confidence level. The mass of charginos was found to be greater than 85.5~GeV/$c^2$ for $m_{ ilde{chi}^+_1}-m_{ ilde{ au}_1}geq 0.3 {mathrm{GeV}}/c^2$, independently of the mass of the gravitino.

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…

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…

A measurement of the mean lifetimes of charged and neutral B-hadrons

The decays of B-hadrons have been reconstructed using the charged particles recorded in the DELPHI silicon microstrip detector. The sum of the charges of the secondaries determines the charge of the B-hadron parent. Some 232 114 multihadronic Z0 decays recorded during the 1991 run of LEP at centre-of-mass energies between 88.2 GeV and 94.2 GeV yield 253 B-hadron candidates with well-measured charge. From these the mean lifetimes of neutral and charged B-hadrons are found to be 1.44 +/- 0.21(stat.) +/- 0.14(syst.) ps and 1.56 +/- 0.19(stat.) +/- 0.13(syst.) ps respectively. The ratio of their lifetimes is 1.09(-0.23)+0.28 (Stat.) +/- 0.11 (syst.). Under some assumptions on the abundance and …

Exclusive production ofDs+Ds−,Ds*+Ds−, andDs*+Ds*−viae+e−annihilation with initial-state radiation

We perform a study of exclusive production of D{sub s}{sup +}D{sub s}{sup -}, D{sub s}{sup *+}D{sub s}{sup -}, and D{sub s}{sup *+}D{sub s}{sup *-} final states in initial-state-radiation events from e{sup +}e{sup -} annihilations at a center-of-mass energy near 10.58 GeV, to search for charmonium 1{sup --} states. The data sample corresponds to an integrated luminosity of 525 fb{sup -1} and was recorded by the BABAR experiment at the PEP-II storage ring. The D{sub s}{sup +}D{sub s}{sup -}, D{sub s}{sup *+}D{sub s}{sup -}, and D{sub s}{sup *+}D{sub s}{sup *-} mass spectra show evidence of the known {psi} resonances. Limits are extracted for the branching ratios of the decays X(4260){yields}…

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…

Measurement of the Z$^0$ branching fraction to b quark pairs using the boosted sphericity product

Abstract From a sample of about 120 000 hadronic Z 0 decays, using a technique based on a separation of the different event categories in the boosted sphericity product, the fraction of b b decays has been measured to be 0.219 ± 0.014 (stat)± 0.019 (syst). Using the DELPHI determination of the hadronic Z 0 width, this corresponds to a partial width τ b b = 378 ± 42 MeV (in good agreement with the standard model prediction of ∼-380 MeV). Combining this measurement with the determinations based on events with high p t leptons gives an estimate for the branching ratio of b into leptons at LEP of (11.2 ± 1.2)%, consistent with previous determinations.

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(-).

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).

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}.

Searches for heavy neutrinos from Z decays

We have searched for possible fourth family heavy neutrinos, pair produced in Z0 decays, in a sample of about 112 000 hadronic Z0 final states collected with the DELPHI detector. For all mixing matrix elements we exclude a new Dirac neutrino lighter than 44.5 GeV at a 95% confidence level, if the neutrino couples to the electron or muon family, and lighter than 44.0 GeV, if the neutrino couples to the tau family. Depending on the values of the mixing element and to which lepton family the neutrino couples, we obtain mass limits up to 46.2 GeV. For all mixing matrix elements we exclude a new Majorana neutrino lighter than 39.0 GeV, if it couples to the electron or the muon family, and lighte…

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.

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 …

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.

Search For Light Neutral Higgs Particles Produced In Z0-decays

A search for the neutral Higgs boson in Z0-decays has been performed using the DELPHI detector at the Large Electron Positron collider (LEP) at CERN. We looked for the decay of Z0 into a neutral Higgs particle and a pair of fermions. No events fulfilled the criteria for H0-production. Our results, which are based on an integrated luminosity of 530 nb-1, exclude a minimal Standard Model Higgs boson with a mass in the range 210 MeV/c2 to 14 GeV/c2 at 95% confidence level.

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…

Analysis of theD+→K−π+e+νedecay channel

Using 347.5  fb^(-1) of data recorded by the BABAR detector at the PEP-II electron-positron collider, 244×10^3 signal events for the D^+ → K^-π^+e^+ν_e decay channel are analyzed. This decay mode is dominated by the K ^*(892)^0 contribution. We determine the K ^*(892)^0 parameters: m_(K^*(892)^0)=(895.4±0.2±0.2)  MeV/c^2, Γ_(K^*(892)^0)=(46.5±0.3±0.2)  MeV/c^2, and the Blatt-Weisskopf parameter r_(BW) =2.1±0.5±0.5  (GeV/c)^-1, where the first uncertainty comes from statistics and the second from systematic uncertainties. We also measure the parameters defining the corresponding hadronic form factors at q^2 = 0 (r_V = ^(V(0))/_(A1(0)) = 1.463 ± 0.017 ± 0.031, r_2 = _(A1(0)) ^(A2(0))= 0.801±0…

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.

A measurement of the \(\tau\) leptonic branching fractions

Abstract: A sample of 25000 Z(0) --> tau(-)tau(+) events collected by the DELPHI experiment at LEP in 1991 and 1992 is used to measure the leptonic branching fractions of the tau lepton. The results are B(tau --> e nu) = (17.51+/-0.39)% and B(tau --> mu nu) = (17.02+/-0.31)%. The ratio of the muon and electron couplings to the weak charged current is measured to be g(mu)/g(e) = 1.000+/-0.013, satisfying e-mu universality. The average leptonic branching fraction corrected to the value for a massless lepton, assuming e-mu universality, is found to be B(tau --> l nu) = (17.50+/-0.25)%.

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 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…

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.

Search for supersymmetric particles in scenarios with a gravitino LSP and stau NLSP

Sleptons, neutralinos and charginos were searched for in the context of scenarios where the lightest supersymmetric particle is the gravitino. It was assumed that the stau is the next-to-lightest supersymmetric particle. Data collected with the DELPHI detector at a centre-of-mass energy near 189 GeV were analysed combining the methods developed in previous searches at lower energies. No evidence for the production of these supersymmetric particles was found. Hence, limits were derived at 95% confidence level.

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 ${\mathcal{B}}(\eta_b\to \tau^+\tau^-)<8%$.

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…

Evidence for the Rare DecayB→K*ℓ+ℓ−and Measurement of theB→Kℓ+ℓ−Branching Fraction

We present evidence for the flavor-changing neutral current decay B-->K-*.(+).(-) and a measurement of the branching fraction for the related process B-->K.(+).(-), where .(+).(-) is either an e(+)e(-) or a mu(+)mu(-) pair. These decays are highly suppressed in the standard model, and they are sensitive to contributions from new particles in the intermediate state. The data sample comprises 123x10(6) Y(4S)-->B (B) over bar decays collected with the BABAR detector at the SLAC PEP-II e(+)e(-) storage ring. Averaging over K-(*) isospin and lepton flavor, we obtain the branching fractions B(B-->Kl(+)l(-))=(0.65(-0.13)(+0.14)+/-0.04)x10(-6) and B(B-->K(*)l(+)l(-))=(0.88(-0.29)(+0.33)+/-0.10)x10(…

Limits onD0−D¯0Mixing andCPViolation from the Ratio of Lifetimes for Decay toK−π+,K−K+, andπ−π+

We present a measurement of D0-macro D0 mixing parameters using the ratios of lifetimes extracted from samples of D0 mesons decaying to K-pi(+), K-K+, and pi(-)pi(+). Using 91 fb(-1) of data collected by the BABAR detector at the PEP-II asymmetric-energy B Factory, we obtain a value Y=[0.8+/-0.4(stat.)(+0.5)(-0.4)(syst.)]%, which, in the limit of CP conservation, corresponds to the mixing parameter y=Delta Gamma/2 Gamma. Using the difference in lifetimes of D0 and macro D0 mesons, we obtain the CP-violation parameter Delta Y=[-0.8+/-0.6(stat.)+/-0.2(syst.)]%.

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} {…

PRODUCTION-RATE AND DECAY LIFETIME MEASUREMENTS OF B(S)0 MESONS AT LEP USING D(S) AND PHI MESONS

The study of the properties of inclusive production of Ds mesons and of events in which a φ{symbol} and a muon are present in the same jet provides two independent measurements of the probability, fs w, for a heavy quark to hadronize into a strange B or D meson. The data sample analysed corresponds to 243,000 hadronic Z0 decays. The combined value of these measurements is fs w=0.19±0.06±0.08. From the flight distance distributions of Ds and of (φ{symbol}-lepton) secondary vertices, with the lepton emitted at high transverse momentum relative to the jet axis, two values are obtained for the Bs 0 meson lifetime. Combining these measurements with a previous result based on the study of Ds-μ ev…

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).

A measurement of αs from the scaling violation in e+e- annihilation

The hadronic fragmentation functions of the various quark flavours and of gluons are measured in a study of the inclusive hadron production from $\zz$ decays with the DELPHI detector and are compared with the fragmentation functions measured elsewhere at energies between 14 GeV and 91 GeV. A large scaling violation is observed, which is used to extract the strong coupling constant from a fit using a numerical integration of the second order DGLAP evolution equations. The result is \begin{displaymath} \alpha_s(M_Z) = 0.124^{+0.006}_{-0.007}(exp)\pm 0.009 (theory) \end{displaymath} where the first error represents the experimental uncertainty and the second error is due to the factorization a…

Energy dependence of event shapes and of $\alpha_s$ at LEP 2

Infrared and collinear safe event shape distributions and their mean values are determined using the data taken at five different centre of mass energies above M-Z with the DELPHI detector at LEP. From the event shapes, the strong coupling alpha(s) is extracted in O(alpha(s)(2)), NLLA and a combined scheme using hadronisation corrections evaluated with fragmentation model generators as well as using an analytical power ansatz. Comparing these measurements to those obtained at M-Z, the energy dependence (running) of alpha(s) is accessible. The logarithmic energy slope of the inverse strong coupling is measured to be d alpha(s)(-1)/d log(E-cm) = 1.39 +/- 0.34 (stat) +/- 0.17(syst), in good ag…

Study of dimuon production in photon-photon collisions and measurement of QED photon structure functions at LEP

Muon pair production in the process e+e- -> e+e-mu+mu- is studied using the data taken at LEP1 (sqrt(s) \simeq m_Z) with the DELPHI detector during the years 1992-1995. The corresponding integrated luminosity is 138.5 pb^{-1}. The QED predictions have been tested over the whole Q^2 range accessible at LEP1 (from several GeV^2/c^4 to several hundred GeV^2/c^4) by comparing experimental distributions with distributions resulting from Monte Carlo simulations using various generators. Selected events are used to extract the leptonic photon structure function F_2^\gamma. Azimuthal correlations are used to obtain information on additional structure functions, F_A^\gamma and F_B^\gamma, which orig…

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 Time-DependentCPAsymmetries and Constraints onsin(2β+γ)with Partial Reconstruction ofB0→D*∓π±Decays

We present a preliminary measurement of the time-dependent CP-violating asymmetry in decays of neutral B mesons to the final states D*-+ pi+- using approximately 178 million BB events recorded by the BaBar experiment at the PEP-II 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 amplitude of the asymmetry to be $-0.041 \pm 0.016 (stat.) \pm 0.010 (syst.)$ and determine bounds on $|\sin(2 \beta + \gamma)|$.

Charged particle multiplicity in e^{+}e_{-}$ → q[L:q] events at 161 and 172 GeV and from the decay of the W boson

The data collected by DELPHI in 1996 have been used to measure the average charged particle multiplicities and dispersions in $q\bar{q}$ events at centre-of-mass energies of $\sqrt{s}=161$~GeV and $\sqrt{s}=172$~GeV, and the average charge multiplicity in WW events at $\sqrt{s}=172$~GeV. The multiplicities in $q\bar{q}$ events are consistent with the evolution predicted by QCD. The dispersions in the multiplicity distributions are consistent with Koba-Nielsen-Olesen (KNO) scaling. The average multiplicity of charged particles in hadronic W decays has been measured for the first time; its value, $19.23 \pm 0.74 (stat+syst)$, is consistent with that expected for an $e^+e^-$ interaction at a c…

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…

Single intermediate vector boson production in e(+)e(-) collisions at root s=183 and 189 GeV

The cross sections for the production of single charged and neutral intermediate vector bosons were measured using integrated luminosities of 52 pb-1 and 154 pb-1 collected by the experiment at centre-of-mass energies of 182.6 GeV and 188.6 GeV, respectively. The cross sections for the reactions were determined in limited kinematic regions. The results found are in agreement with the Standard Model predictions for these channels. © 2001 Elsevier Science B.V.

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 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 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 pair production of neutral Higgs bosons in Z$^0$ decays

The pair production of the lightest scalar Higgs boson, h, and a pseudoscalar Higgs boson, A, was searched for in a data sample containing 10 000 hadronic Z0 decays. The search involved both leptonic and purely hadronic decay channels of each Higgs boson. No signal was found, and limits on the Higgs boson masses, in the framework of the minimal supersymmetric extension of the standard model, ar reported up to 35 GeV/c2 at 95% CL, for both tan β > 1 and tan β < 1, where tan β is the ratio of the vacuum expectation values of the two Higgs doublets.

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.

Measurement of the transverse spin correlation in Z → τ+ τ- decays

The measurement of the correlation between the transverse spin components of tau(+)tau(-) pairs collected during 1992 to 1994 with the DELPHI detector at LEP1 is presented. A value C-TT = 0.87 +/- 0.20 (stat.)(-0.12)(+0.10) (syst.) was obtained for the correlation parameter, in agreement with the Standard Model expectation. (C) 1997 Published by Elsevier Science B.V.

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…

A study of intermittency in Hadronic Z$^0$ Decays

The correlations in rapidity in hadron production from e+e- annihilation near the Z0 resonance were studied by means of the method of factorial moments, using data taken with the DELPHI detector at LEP. The parton shower hadronization model was found to be in quantitative agreement with the data, in contrast with previous results at lower energies. © 1990.

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.

Multiplicity fluctuations in hadronic final states from the decay of the Z0

An analysis of the fluctuations in the phase space distribution of hadrons produced in the decay of 78829 Z0 has been carried out, using the method of factorial moments. The high statistics collected by the DELPHI experiment at LEP during 1990 allowed studies of the event sample both globally and in intervals of p(t) and multiplicity, and for different jet topologies and for single jets. A large contribution to the factorial moments of the one-dimensional data on rapidity with respect to the event axis comes from hard gluons. Details of factorial moments in two and three dimensions are presented. Influences of resonance decays have been studied by Monte Carlo simulation: one-dimensional fac…

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 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…

Measurement of the spin density matrix for the rho(0), K*(0)(892) and phi produced in Z(0) decays

The spin density matrix elements for the rho(0), K-*0(892) and phi produced in hadronic Z(0) decays are measured in the DELPHI detector. There is no evidence for spin alignment of the K-*0(892) and phi, in the region x(p) less than or equal to 0.3 (x(p) = p/p(beam)), where rho(00) = 0.33 +/- 0.05 and rho(00) = 0.30 +/- 0.04, respectively. In the fragmentation region, x(p) greater than or equal to 0.4, there is some indication for spin alignment of the rho(0) and K-*0(892), since rho(00) = 0.43 +/- 0.05 and rho(00) = 0.46 +/- 0.08, respectively. These values are compared with those found in meson-induced hadronic reactions. For the phi, rho(00) = 0.30 +/- 0.04 for x(p) greater than or equal …

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} {+-…

Classification of the hadronic decays of the Z$^0$ into b and c quark pairs using a neural network

A classifier based on a feed-forward neural network has been used for separating a sample of about 123 500 selected hadronic decays of the Z 0 , collected by DELPHI during 1991, into three classes according to the flavour of the original quark pair: u u +d d +s s (unresolved), c c and b b . The classification has been used to compute the partial widths of the Z 0 into b and c quark pairs. This gave Γ c c /Γ h = 0.151 ± 0.008 ( stat. ) ± 0.041 ( syst. ) , Γ b b /Γ h = 0.232±0.005 ( stat. )±0.017 ( syst. ) .

Observation ofB0→ωK0,B+→ηπ+, andB+→ηK+and Study of Related Decays

We present measurements of branching fractions and charge asymmetries for seven B-meson decays with an eta, eta', or omega meson in the final state. The data sample corresponds to 89x10(6) BB pairs produced from e(+)e(-) annihilation at the Upsilon(4S) resonance. We measure the following branching fractions in units of 10(-6): B(B+-->eta pi(+))=5.3+/-1.0+/-0.3, B(B+-->eta K+)=3.4+/-0.8+/-0.2, B(B0-->eta K0)=2.9+/-1.0+/-0.2 ( eta(')pi(+))=2.7+/-1.2+/-0.3 ( omega pi(+))=5.5+/-0.9+/-0.5, B(B+-->omega K+)=4.8+/-0.8+/-0.4, and B(B0-->omega K0)=5.9(+1.6)(-1.3)+/-0.5. The charge asymmetries are A(ch)(B+-->eta pi(+))=-0.44+/-0.18+/-0.01, A(ch)(B+-->eta K+)=-0.52+/-0.24+/-0.01, A(ch)(B+-->omega pi(+…

Search forB+meson decay toa1+(1260)K*0(892)

We present a search for the decay B{sup +} --> {alpha}{sup +}{sub 1}(1260)K*{sup 0}(892). The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, represent 465 million B{anti B} pairs produced in e{sup +}e{sup -} annihilation at the energy of the {Upsilon}(4S). We find no significant signal and set an upper limit at 90% confidence level on the product of branching fractions B(B{sup +} --> {alpha}{sup +}{sub 1}(1260)K*{sup 0}(892)) x B({alpha}{sup +}{sub 1}(1260) --> {pi}{sup +}{pi}{sup -}{pi}{sup +}) of 1.8 x 10{sup -6}.

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…

Measurement of $\Delta^{++}$(1232) production in hadronic Z decays

A measurement of the \Delta^{++}(1232) inclusive production in hadronic decays of the Z at LEP is presented, based on 1.3 million hadronic events collected~ by the DELPHI~ detector in the 1994 LEP running~ period. The DELPHI ring imaging Cherenkov counters are used for identifying hadrons. The average \Delta^{++}(1232) multiplicity per hadronic event is 0.079 \pm 0.015 which is more than a factor of two below the JETSET, HERWIG and UCLA model predictions. It agrees with a recently proposed universal mass dependence of particle production rates in e^{+}e^- annihilations.

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…

Measurement of correlations between pions from different W's in e+e- → W+W- events

Correlations between pions from different W's in e(+)e(-) --> W+W- events are studied using data collected by the DELPHI detector at LEP running at a centre-of-mass energy of 172 GeV in 1996. At the present level of statistics, no enhancement of the correlation function above that expected from a pair of uncorrelated W's is observed at small values of the four-momentum difference of the pions. (C) 1997 Published by Elsevier Science B.V.

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.

Two-particle angular correlations in e(+)e(-) interactions compared with QCD predictions

Two-particle angular correlations in jet cones have been measured in e(+)e(-) annihilation into hadrons at LEP energies (root s = 91 and 183 GeV) and are compared with QCD predictions using the LPHD hypothesis. Two different functions have been tested. While the differentially normalized correlation function shows substantial deviations from the predictions, a globally normalized correlation function agrees well. The size of alpha(s)(eff) land other QCD parameters) and its running with the relevant angular scale, the validity of LPHD, and problems due to non-perturbative effects are discussed critically. (C) 1998 Elsevier Science B.V. All rights reserved.

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.

A precise measurement of the Z resonance parameters through its hadronic decays

A measurement of the cross section for e+e-→ hadrons using 11 000 hadronic decays of the Z boson at ten different center-of-mass energies is presented. A three-parameter fit gives the following values for the Z mass MZ, the total width ΓZ, the product of the electronic and hadronic partial widths ΓeΓh, and the unfolded pole cross section σ0: MZ = 91.171 ± 0.030 (stat.) ± 0.030 (beam) GeV, ΓZ = 2.511 ± 0.065 GeV, ΓeΓh = 0.148 ± 0.006 (stat.) ± 0.004 (syst.) GeV2, σ0 = 41.6 ± 0.7 (stat.) ± 1.1 (syst.) nb, Good agreement with the predictions of the standard model is observed. From a two-parameter fit the number of massless neutrino generations is found to be Nv = 2.91 ± 0.26. Thus the hypothes…

A study of the Lorentz structure in tau decays

This paper describes a measurement of the Michel parameters, \eta, \rho, \xi, \xi\delta, and the average \nu_{\tau} helicity, h_{\nu_{\tau}}, in tau lepton decays together with the first measurement of the tensor coupling in the weak charged current. The tau+tau- pairs were produced at the LEP e+e- collider at CERN from 1992 through 1995 in the DELPHI detector. Assuming lepton universality in the decays of the tau the measured values of the parameters were: \eta = -0.005 +/- 0.036 +/- 0.037, \rho = 0.775 +/- 0.023 +/- 0.020, \xi = 0.929 +/- 0.070 +/- 0.030, \xi\delta = 0.779 +/- 0.070 +/- 0.028, h_{\nu_{\tau}} = -0.997 +/- 0.027 +/- 0.011. The strength of the tensor coupling was measured to…

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}…

Search for a fermiophobic Higgs at LEP 2

Higgs bosons predicted by the fermiophobic scenario within Two Higgs Doublets Models were searched for in the data collected by the DELPHI detector at centre-of-mass energies between 189 GeV and 202 GeV, corresponding to a total integrated luminosity of 380 pb^{-1}. No signal was found and confidence limits were derived in the framework of possible extensions of the Standard Model Higgs sector.

Observation and study of the baryonicB-meson decaysB→D(*)pp¯(π)(π)

We present results for B-meson decay modes involving a charm meson, protons, and pions using 455×106 BB pairs recorded by the BaBar detector at the SLAC PEP-II asymmetric-energy e^+e^- collider. The branching fractions are measured for the following ten decays: B ^0→D^0pp, B^0→D^(*0)pp, B^0→D^(*+)ppπ^-, B^0→D^(*+)ppπ^-, B-→D0ppπ^-, B-→D^(*0)ppπ^-, B^0→D^0pp π^-π^+, B^0→D^(*0)pp π^-π^+, B^-→D^+pp π^-π^-, and B^-→D^(*+)pp π^-π^-. The four B^- and the two five-body B^0 modes are observed for the first time. The four-body modes are enhanced compared to the three- and the five-body modes. In the three-body modes, the M(pp) and M(D^((*)0)p) invariant-mass distributions show enhancements near thre…

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…

Energy dependence of the differences between the quark and gluon jet fragmentation

Three jet events arising from decays of the Z beson, collected by the DELPHI detector, were used to measure differences in quark and gluon fragmentation. Gluon jets were anti-tagged by identifying b quark jets. Unbiased quark jets came from events with two jets plus one photon. Quark and gluon jet properties in different energy ranges were compared for the first time within the same detector. Quark and gluon jets of nearly the same energy in symmetric three jet event topologies were also compared. Using three independent methods, the average value of the ratio of the mean charged multiplicities of gluon and quark jets is [ r ] = 1.241 +/- 0.015 (stat.) +/- 0.025 (syst.). Gluon jets are broa…

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 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 the rare decayB→Kνν¯

We present a search for the rare decays B+→K+νν and B0→K0νν using 459×106 BB pairs collected with the BABAR detector at the SLAC National Accelerator Laboratory. Flavor-changing neutral-current decays such as these are forbidden at tree level but can occur through one-loop diagrams in the standard model (SM), with possible contributions from new physics at the same order. The presence of two neutrinos in the final state makes identification of signal events challenging, so reconstruction in the semileptonic decay channels B→D(*)lν of the B meson recoiling from the signal B is used to suppress backgrounds. We set an upper limit at the 90% confidence level (CL) of 1.3×10-5 on the total branch…

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…

Studies ofτ−→ηK−ντandτ−→ηπ−ντatBABARand a search for a second-class current

We report on analyses of tau lepton decays τ-→ηK-ντ and τ-→ηπ-ντ, with η→π+π-π0, using 470  fb-1 of data from the BABAR experiment at PEP-II, collected at center-of-mass energies at and near the Υ(4S) resonance. We measure the branching fraction for the τ-→ηK-ντ decay mode, B(τ-→ηK-ντ)=(1.42±0.11(stat)±0.07(syst))×10-4, and report a 95% confidence level upper limit for the second-class current process τ-→ηπ-ντ, B(τ-→ηπ-ντ)<9.9×10-5.

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.

Experimental study of the triple-gluon vertex

Abstract In four-jet events from e+e− →Z0 →multihadrons one can separate the three principal contributions from the triple-gluon vertex, double gluon-bremsstrahlung and the secondary quark-antiquark production, using the shape of the two-dimensional angular distributions in the generalized Nachtmann-Reiter angle θ NR ∗ and the opening angle of the secondary jets. Thus one can identify directly the contribution from the triple-gluon vertex without comparison with a specific non-QCD model. Applying this new method to events taken with the DELPHI-detector we get for the ratio of the colour factor Nc to the fermionic Casimir operator C F : N c C F = 2.55 ± 0.55 ( stat. ) ± 0.4 ( fragm. + models…

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 ${\cal A}_1(w=1)$. …

Study of the leptonic decays of the Z0 boson

Measurements are presented of the cross section ratios Rℓ = σℓ(e+e-→ℓ+ℓ -)/σhh(e+e-→hadrons) for ℓ = e, μ and τ using data taken from a scan around the Z0. The results are Re = (5.09±0.32±0.18)%, Rμ = (4.96±0.35±0.17)% and Rτ,=(4.72±0.38± 0.29)% where, for the ratio Re, the t-channel contribution has been subtracted. These results are consistent with the hypothesis of lepton universality and test this hypothesis at the energy scale s ∼ 8300 GeV2. The absolute cross sections σℓ(e+e-→ℓ +ℓ-) have also been measured. From the cross sections the leptonic partial widths Γe = (83.2±3.0±2.4) MeV, (ΓeΓμ) 1/2=(84.6±3.0±2.4) MeV and (ΓeΓτ) 1/2=(82.6±3.3±3.2) MeV have been extracted. Assuming lepton un…

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 …

Determination of |Vub|/|Vcb| with DELPHI at LEP

The ratio of the CKM quark-mixing matrix elements |Vub|/|Vcb| has been measured using B hadron semileptonic decays. The analysis uses the reconstructed mass M_X of the secondary hadronic system produced in association with an identified lepton. Since B -&gt; X_u lepton anti-nu transitions are characterised by hadronic masses below those of the D mesons produced in B -&gt; X_c lepton anti-nu transitions, events with a reconstructed value of M_X significantly below the D mass are selected. Further signal enrichments are obtained using the topology of reconstructed decays and hadron identification. A fit to the numbers of decays in the b -&gt; u enriched and depleted samples with M_X above and…

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 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 …

A Search for Heavy Stable and Long-Lived Squarks and Sleptons in $e^+ e^-$ Collisions at Energies from 130 to 183 GeV

A search for stable and long-lived heavy charged particles used the data taken by the DELPHI experiment at energies from 130 to 183 GeV. The Cherenkov light detected in the Ring Imaging Cherenkov Detector and the ionization loss measured in the Time Projection Chamber identify heavy particles from masses of 2 to nearly 89 GeV/c$^2$. Upper limits are given on the production cross-section and masses of sleptons, free squarks with a charge of $q = \pm 2/3e$ and hadronizing squarks. A search for stable and long-lived heavy charged particles used the data taken by the DELPHI experiment at energies from 130 to 183 GeV. The Cherenkov light detected in the Ring Imaging Cherenkov Detector and the io…

Measurement of theB→D¯(*)D(*)Kbranching fractions

The authors present a measurement of the branching fractions of the 22 decay channels of the B{sup 0} and B{sup +} mesons to {bar D}{sup (*)}D{sup (*)}K, where the D{sup (*)} and {bar D}{sup (*)} mesons are fully reconstructed. Summing the 10 neutral modes and the 12 charged modes, the branching fractions are found to be {Beta}(B{sup 0} {yields} {bar D}{sup (*)}D{sup (*)}K) = (3.68 {+-} 0.10 {+-} 0.24)% and {Beta}(B{sup +} {yields} {bar D}{sup (*)}D{sup (*)}K) = (4.05 {+-} 0.11 {+-} 0.28)%, where the first uncertainties are statistical and the second systematic. The results are based on 429 fb{sup -1} of data containing 471 x 10{sup 6} B{bar B} pairs collected at the {Upsilon}(4S) resonance…

Measurement of the mass of the W boson using direct reconstruction at √s = 183 GeV

From data corresponding to an integrated luminosity of 53.5 pb(-1) taken during the 183 GeV run in 1997, DELPHI has measured the W mass from direct reconstruction of WW --> lq (q) over bar and WW --> q (q) over bar q (q) over bar events. Combining these channels, a value of m(w) = 80.238 +/- 0.154(stat) +/- 0.035(syst) +/- 0.035(fsi) +/- 0.021 (LEP) GeV/c(2) is obtained, where fsi denotes final state interaction. Combined with the W mass obtained by DELPHI from the WW production cross-section and with the direct measurement at 172 GeV this leads to a measured value of m(w) = 80.270 +/- 0.137(stat) +/- 0.031(syst) +/- 0.030(fsi) +/- 0.021(LEP)GeV/c(2), in good agreement with the Standard Mod…

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.

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…

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.

Study of High Momentumη′Production inB→η′Xs

We measure the branching fraction for the charmless semi-inclusive process B --> eta'Xs, where the eta' meson has a momentum in the range 2.0 to 2.7 GeV/c in the upsilon4S center-of-mass frame and Xs represents a system comprising a kaon and zero to four pions. We find B(B --> eta'Xs) = [3.9 +/- 0.8(stat) +/- 0.5(syst) +/- 0.8(model)] x 10(-4). We also obtain the Xs mass spectrum and find that it fits models predicting high masses.

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…

Study of the four-jet anomaly observed at LEP centre-of-mass energies of 130 and 136 GeV

The four-jet events collected by DELPHI during the special LEP run at centre-of-mass energies of 130 and 136 GeV in 1997 with an integrated luminosity of 5.9 pb(-1) are analysed. Their rate and the distributions of their di-jet masses, their smallest jet charges, and their di-jet charge separations all agree well with Standard Model predictions. Thus the hypothesis of pair production of a new particle with a sum of di-jet masses around 105 GeV/c(2) is not supported. The combined result of the four LEP collaborations refuting this hypothesis at over 99% confidence level is also given. (C) 1999 Published by Elsevier Science B.V. All rights reserved.

Search for the Rare Leptonic Decay B+→μ+νμ

A search for the rare leptonic decay with data collected at the resonance by the BABAR experiment was carried out. The decay rate was sensitive to the product of the Cabibbo Kobayashi Maskawa matrix element (Vub and the B decay constant fb, which was propotional to the wave function for zero separation between the quarks. The data used in the analysis was collectd with BABAR detector at the PEP-II storage ring and the sample consisted of an integrity luminosity of 81.4 fb-1. The systematic uncertainty in the signal efficiency was evaluated which included the muon candidate selection and the reconstruction efficiency of the companion B.

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-+/-.

Observation ofηc(1S)andηc(2S)decays toK+K−π+π−π0in two-photon interactions

We study the processes γγ→K_S^0K^±π^∓ and γγ→K^+K^-π^+π-π^0 using a data sample of 519.2fb^(-1) recorded by the BABAR detector at the PEP-II asymmetric-energy e^+e^- collider at center-of-mass energies near the Υ(nS) (n=2, 3, 4) resonances. We observe the η_c(1S), χ_(c0)(1P) and η_c(2S) resonances produced in two-photon interactions and decaying to K^+K^-π^+π^-π^0, with significances of 18.1, 5.4 and 5.3 standard deviations (including systematic errors), respectively, and report 4.0σ evidence of the χ_(c2)(1P) decay to this final state. We measure the η_c(2S) mass and width in K_S^0K^±π^∓ decays, and obtain the values m(η_c(2S))=3638.5±1.5±0.8  MeV/c^2 and Γ(η_c(2S))=13.4±4.6±3.2  MeV, wher…

Limits on the production of scalar leptoquarks from $Z^0$ decays at LEP

A search has been made for pairs and for single production of scalar leptoquarks of the first and second generations using a data sample of 392000 Z0 decays from the DELPHI detector at LEP 1. No signal was found and limits on the leptoquark mass, production cross section and branching ratio were set. A mass limit at 95% confidence level of 45.5 GeV/c2 was obtained for leptoquark pair production. The search for the production of a single leptoquark probed the mass region above this limit and its results exclude first and second generation leptoquarks D0 with masses below 65 GeV/c2 and 73 GeV/c2 respectively, at 95% confidence level, assuming that the D0lq Yukawa coupling alpha(lambda) is equ…

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(+/-).

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 …

Measurements of the branching fractions and bounds on the charge asymmetries of charmless three-body charged B decays.

We present measurements of branching fractions and charge asymmetries for charmless B-meson decays to three-body final states of charged pions and kaons. The analysis uses 81.8 fb^-1 of data collected at the Upsilon(4S) resonance with the BaBar detector at the SLAC PEP-II asymmetric B Factory. We measure the branching fractions B(B+ -&gt; pi+ pi- pi+) = (10.9 +/- 3.3 +/- 1.6) x 10^-6, B(B+ -&gt; K+ pi- pi+) = (59.1 +/- 3.8 +/- 3.2) x 10^-6, and B(B+ -&gt; K+ K- K+) = (29.6 +/- 2.1 +/- 1.6) x 10^-6, and provide 90% C.L. upper limits for other decays. We observe no charge asymmetries for these modes.

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.).

Consistent measurements of alpha(s) from precise oriented event shape distributions

An updated analysis using about 1.5 million events recorded at $\sqrt{s} = M_Z$ with the DELPHI detector in 1994 is presented. Eighteen infrared and collinear safe event shape observables are measured as a function of the polar angle of the thrust axis. The data are compared to theoretical calculations in ${\cal O} (\alpha_s^2)$ including the event orientation. A combined fit of $\alpha_s$ and of the renormalization scale $x_{\mu}$ in $\cal O(\alpha_s^2$) yields an excellent description of the high statistics data. The weighted average from 18 observables including quark mass effects and correlations is $\alpha_s(M_Z^2) = 0.1174 \pm 0.0026$. The final result, derived from the jet cone energ…

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.

A Measurement of Sin2-theta-w From the Charge Asymmetry of Hadronic Events At the Z0 Peak

Abstract View references (24)The weak mixing angle has been measured from the charge asymmetry of hadronic events with two different approaches using the DELPHI detector at LEP. Both methods are based on a momentum-weighted charge sum to determine the jet charge in both event hemispheres. In a data sample of 247 300 multihadronic Z0 decays a charge asymmetry of 〈QF〉 - 〈QB〉 = -0.0076±0.0012(stat.)±0.0005(exp. syst.)±0.0014(frag.) and a raw forward-backward asymmetry of Araw FB = -0.0109±0.0020(stat.)±0.0010(exp. syst.)±0.0017(frag.) have been measured. This result corresponds to a value of sinθeff=0.2345±0.0030(exp.)±0.0027(frag.) ,sin2θMS=0.2341±0.0030(exp.)±0. 0027(frag.) and to sin2θW=1-m…

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 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.

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.

Observation of a Narrow Meson State Decaying toDs+π0at a Mass of2.32  GeV/c2

We have observed a narrow state near 2.32 GeV/c(2) in the inclusive D(+)(s)pi(0) invariant mass distribution from e(+)e(-) annihilation data at energies near 10.6 GeV. The observed width is consistent with the experimental resolution. The small intrinsic width and the quantum numbers of the final state indicate that the decay violates isospin conservation. The state has natural spin-parity and the low mass suggests a J(P)=0(+) assignment. The data sample corresponds to an integrated luminosity of 91 fb(-1) recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)e(-) storage ring.

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.

Cross-sections and leptonic forward-backward asymmetries from the Z(0) running of LEP

During 1993 and 1995 LEP was run at 3 energies near the Z $^0$ peak in order to give improved measurements of the mass and width of the resonance. During 1994, LEP operated only at the Z $^0$ peak. In total DELPHI accumulated data corresponding to an integrated luminosity of approximately 116 pb $^{-1}$ . Analyses of the hadronic cross-sections and of the cross-sections and forward-backward asymmetries in the leptonic channels used the most precise evaluations of the LEP energies. In the dimuon channel, events with a photon radiated from the initial state have been used to probe the cross-sections and asymmetries down to PETRA energies. Model independent fits to all DELPHI lineshape and asy…

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 …

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…

Search for scalar quarks in Z0 decays

A search has been made for pairs of scalar quarks (squarks) produced in e+e- annihilations at LEP (√s≃MZ0), and decaying into a standard quark and a neutral, non-interacting, stable, massive particle (the lightest supersymmetric particle, LSP). The search has been conducted for differences in the mass of the squark and LSP of 2 GeV/c2 and above. Up squarks with masses below 42 GeV/c2 and down squarks below 43 GeV/c2 were excluded. Six squark flavours degenerate in mass were excluded below 45 GeV/c2.

Multiplicity dependence of mean transverse momentum in $e^+e^-$ annihilations at LEP energies

A strong increase of the mean transverse momentum [p(t)] with the number of charged particles n(ch) is observed in e+e- annihilations into hadrons at LEP energies, The effect resembles correlations observed in hadron-hadron interactions. In e+e- annihilations the [p(t)] and n(ch) correlations can be accounted for by gluon radiation.

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+…

Charged particle multiplicity distributions in restricted rapidity intervals in Z0 hadronic decays.

The multiplicity distributions of charged particles in restricted rapidity intervals in Z0 hadronic decays measured by the DELPHI detector are presented. The data reveal a shoulder structure, best visible for intervals of intermediate size, i.e. for rapidity limits around ±1.5. The whole set of distributions including the shoulder structure is reproduced by the Lund Parton Shower model. The structure is found to be due to important contributions from 3-and 4-jet events with a hard gluon jet. A different model, based on the concept of independently produced groups of particles, "clans", fluctuating both in number per event and particle content per clan, has also been used to analyse the pres…

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 …

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.

Determination of 55-155-155-1in second order QCD from hadronic Z decays

Distributions of event shape variables obtained from 120600 hadronic Z decays measured with the DELPHI detector are compared to the predictions of QCD based event generators. Values of the strong coupling constant αs are derived as a function of the renormalization scale from a quantitative analysis of eight hadronic distributions. The final result, αs(MZ), is based on second order perturbation theory and uses two hadronization corrections, one computed with a parton shower model and the other with a QCD matrix element model. © 1992 Springer-Verlag.

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 inclusive ρ0, f0(980), f2(1270), K and f′2(1525) production in Z0 decays

DELPHI results are presented on the inclusive production of the neutral mesons ρ0, f0(980), f2(1270), KView the MathML source and f′2(1525) in hadronic Z0 decays. They are based on about 2 million multihadronic events collected in 1994 and 1995, using the particle identification capabilities of the DELPHI Ring Imaging Cherenkov detectors and measured ionization losses in the Time Projection Chamber. The total production rates per hadronic Z0 decay have been determined to be: 1.19±0.10 for ρ0; 0.164±0.021 for f0(980); 0.214±0.038 for f2(1270); 0.073±0.023 for KView the MathML source; and 0.012±0.006 for f′2(1525). The total production rates for all mesons and differential cross-sections for …

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).

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…

Lifetime and production rate of beauty baryons from Z decays

The production and decay of beauty baryons (b-baryons) have been studied using 1.7 \times 10^6 Z hadronic decays collected by the DELPHI detector at LEP. Three different techniques were used to identify the b-baryons. The first method used pairs of a \Lambda and a lepton to tag the b-baryon decay. The second method associated fully reconstructed \Lambda_c baryons with leptons. The third analysis reconstructed the b-baryon decay points by forming secondary vertices from identified protons and muons of opposite sign. Using these methods the following production rates were measured: \begin{eqnarray*} f(\qb \ra \Bb) \times \BR(\Bb \ra \mLs \ell\bar{\nu}_{\ell}\X) & = & (0.30 \pm 0.06 \pm0.04)\%…

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.

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…

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.

Observation of the DecayB±→π±π0, Study ofB±→K±π0, and Search forB0→π0π0

We present results for the branching fractions and charge asymmetries in B+/--->h(+/-)pi(0) (where h(+/-)=pi(+/-),K+/-) and a search for the decay B0-->pi(0)pi(0) using a sample of approximately 88 x 10(6) BBmacr; pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We measure B(B+/--->pi(+/-)pi(0))=(5.5(+1.0)(-0.9)+/-0.6)x10(-6), where the first error is statistical and the second is systematic. The B+/--->pi(+/-)pi(0) signal has a significance of 7.7sigma including systematic uncertainties. We simultaneously measure the K+/-pi(0) branching fraction to be B(B+/--->K+/-pi(0))=(12.8(+1.2)(-1.1)+/-1.0)x10(-6). The charge asymmetries are Api(+/-)(pi(0))=-0.0…

Measurement of the Branching Fraction and Polarization for the DecayB−→D*0K*−

We present a study of the decay B- --> D*K-0*(-) based on a sample of 86 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 measure the branching fraction 23(B- --> D*K-0*(-)) = (8.3 +/- 1.1(stat) +/- 1.0(syst)) X 10(-4), and the fraction of longitudinal polarization in this decay to be Gamma(L)/Gamma = 0.86 +/- 0.06(stat) --> +/- 0.03(syst).

Search for charged Higgs bosons in e^{+}e^{-}$ collisions at √s=172 GeV

This paper presents results on charged Higgs boson production, based on LEP data collected at √s = 172 GeV, that complement the previous DELPHI results obtained at centre of mass energies up to 161 GeV. The charged Higgs bosons are assumed to be pair produced and to decay either into a quark pair or into τVτ. The three different possible final states are included in the analysis. Data from ring imaging Cherenkov and microvertex detectors are used to identify the quarks as a cs pair. The number of candidates found is compatible with the background expected from standard processes. Combining the results of the present analysis with those of the previous analysis at lower energies, a new lower…

Measurement of the partial width of the decay of the Z0 into charm quark pairs

A determination of the partial width Γc̄ of the Z0 boson into charm quark pairs is presented, based on a total sample of 36 900 Z0 hadronic decays measured with the DELPHI detector at the LEP collider. The production rate of cc events is derived from the inclusive analysis of charged pions coming from the decay of charmed meson D*+-→D0π+ and D*-→D̄0π- where the π± is constrained by kinematics to have a low pT with respect to the jet axis. The probability to procedure these π± from D*± decay in cc events is taken to be 0.31±0.05 as measured at √S = 10.55 GeV. The measured relative partial width Γ∞/Γh = 0.162± 0.030(stat.) ± 0.050(syst.) is in good agreement with the standard model value of 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.

MEASUREMENT OF THE FORWARD-BACKWARD ASYMMETRY OF CHARM AND BOTTOM QUARKS AT THE Z-POLE USING D-ASTERISK(+/-)-MESONS

The forward-backward asymmetries for the processes $$e^ + e^ - \to c\bar c$$ and $$e^ + e^ - \to b\bar b$$ at theZ resonance are measured using identifiedD *± mesons. In 905,000 selected hadronic events, taken in 1991 and 1992 with the DEL-PHI detector at LEP, 4757D *+→D 0π+ decays are reconstructed. Thec andb quark forward-backward asymmetries are determined to be: $$\begin{gathered} A_{FB}^{c\bar c} = 0.077 \pm 0.029(stat) \pm 0.012(sys), \hfill \\ A_{FB}^{b\bar b} = 0.059 \pm 0.062(stat) \pm 0.024(sys). \hfill \\ \end{gathered} $$ Constraining theb asymmetry to the value measured by DELPHI using independent analyses, the charm asymmetry is determined to be: $$A_{FB}^{c,const} = 0.068 \pm…

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 the trilinear gauge boson couplings WWV (V = $\gamma$ Z) in e$^+$e$^-$ collisions at 183 GeV

Measurements of the trilinear gauge boson couplings WWγ and WWZ are presented from data taken by DELPHI in 1997 at an energy of 183 GeV. From a study of the reactions e + e − → W + W − , e + e − → Weν and e + e − → ννγ , values are obtained for Δg 1 Z and Δκ γ , the differences of the WWZ charge coupling and of the WWγ dipole couplings from their Standard Model values, and for λ γ , the WWγ quadrupole coupling. The observations are consistent with the predictions of the Standard Model. (Elsevier)

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 Lepton-Flavor Violation in the Decayτ−→ℓ−ℓ+ℓ−

A search for the lepton-flavor-violating decay of the tau into three charged leptons has been performed using 91.5 fb(-1) of data collected at an e(+)e(-)center-of-mass energy around 10.58 GeV with the BABAR detector at the SLAC storage ring PEP-II. 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 (1-3)x10(-7) at 90% confidence level.

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.

mb at MZ

Abstract The value of the b quark mass at the M Z scale defined in the MS renormalization scheme, m b ( M Z ), was determined using 2.8 million hadronic Z decays collected during 1992-1994 by the DELPHI detector to be m b (M Z )=2.67±0.25 ( stat. )±0.34 ( frag. )±0.27 ( theo. ) GeV/c 2 . The analysis considers NLO corrections to the three-jet production rate including mass effects, and the result obtained agrees with the QCD prediction of having a running b quark mass at an energy scale equal to M Z . This is the first time that such a measurement is performed far above the b b production threshold. The study also verifies the flavour independence of the strong coupling constant for b and l…

A measurement of the photon structure function F-2(gamma) at an average Q(2) of 12 GeV2/c(4)

The hadronic photon structure function F_{2}^{gamma} has been measured in the Q^{2} range from 4 to 30~GeV^2/c^{4} and down to x values of order 0.001, using data taken with the DELPHI detector at LEP between 1991 and 1993. A comparison is made with several F_{2}^{gamma} parameterizations with special emphasis on their low x behaviour. A result on the Q^{2} evolution of F_{2}^{gamma} is presented.

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 scalar leptoquarks from Z$^0$ decays

We have searched for pair produced scalar leptoquarks each decaying to a quark and a charged lepton in a sample of 116 000 hadronic Z0 events produced at LEP. No candidate was detected and cross section and branching ratio limits are set for the above process at 95% CL. Mass limits are found to be about 42 GeV/c2 depending only slightly on the models used and a coupling times branching ratio exclusion line is drawn for a scalar leptoquark with a free coupling. We have also probed the mass region above 45 GeV/c2 for a singly produced scalar leptoquark and set limits on the cross section and the coupling lambda(2)/4-pi up to 60 GeV.

MEASUREMENT OF THE GAMMA(B-B-OVER-BAR)/GAMMA(HAD) BRANCHING RATIO OF THE Z BY DOUBLE HEMISPHERE TAGGING

Two measurements of {Mathematical expression} are presented. Both measurements use 250000 Z decays taken with the DELPHI detector in 1991 and rely mainly on the precision of the microvertex detector. One tagging method is as simple as possible so that background rates can be reliably predicted by simulation. The other one uses a more involved tagging technique and reduces the dependence on simulation as much as possible. Combining both results, {Mathematical expression} is found to be 0.2209±0.0041(stat.)±0.0042(syst.)±0.0018 {Mathematical expression}. © 1995 Springer-Verlag.

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.

Measurements of the branching fractions of chargedBdecays toK±π∓π±final states

We present results of searches for B-meson decays to K+ pi- pi+ with the BaBar detector. With a data sample of 61.6 million BBbar pairs, we measure the branching fractions and 90% confidence-level upper limits averaged over charge-conjugate states (the first error is statistical and the second is systematic): B+ --> K*0 pi+ = (15.5 +/- 1.8 +1.5 -4.0) x 10^-6, B+ --> f0 K+, f_0 --> pi+ pi- = (9.2 +/- 1.2 +2.1 -2.6) x 10^-6, B+ --> D0bar pi+, D0bar --> K+ pi- = (184.6 +/- 3.2 +/- 9.7) x 10^-6. B+ --> rho K+ K+ pi- pi+ non-resonant < 17 x 10^-6.

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(…