0000000001060237
AUTHOR
T.r. Mcmahon
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…
Ratio of Isolated Photon Cross Sections in pp¯ Collisions at √s=630 and 1800 GeV
The inclusive cross section for production of isolated photons has been measured in p (p) over bar collisions at roots = 630 GeV with the DO detector at the Fermilab Tevatron Collider. The photons span a transverse energy (E-T) range from 7-49 GeV and have pseudorapidity \eta\ s = 1800 GeV to form a ratio of the cross sections. Comparison of next-to-leading-order QCD with the measured cross section at 630 GeV and the ratio of cross sections show satisfactory agreement in most of the E-T range.
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-…
Charged-particle multiplicities in pp interactions at s=900 GeV measured with the ATLAS detector at the LHC
The first measurements from proton-proton collisions recorded with the ATLAS detector at the LHC are presented. Data were collected in December 2009 using a minimum-bias trigger during collisions at a centre-of-mass energy of 900 GeV. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and charged-particle multiplicity are measured for events with at least one charged particle in the kinematic range vertical bar eta vertical bar 500 MeV. The measurements are compared to Monte Carlo models of proton-proton collisions and to results from other experiments at the same centre-of-mass energy. The charg…
Measurement of the centrality dependence of J/ψ yields and observation of Z production in lead–lead collisions with the ATLAS detector at the LHC
Using the ATLAS detector, a centrality-dependent suppression has been observed in the yield of J/psi mesons produced in the collisions of lead ions at the Large Hadron Collider. In a sample of minimum-bias lead-lead collisions at a nucleon-nucleon centre of mass energy root s(NN) = 2.76 TeV, corresponding to an integrated luminosity of about 6.7 mu b(-1), J/psi mesons are reconstructed via their decays to mu(+)mu(-) pairs. The measured J/psi yield, normalized to the number of binary nucleon-nucleon collisions, is found to significantly decrease from peripheral to central collisions. The centrality dependence is found to be qualitatively similar to the trends observed at previous, lower ener…
Measurement of the production cross section for W-bosons in association with jets in pp collisions at s=7 TeV with the ATLAS detector
This Letter reports on a first measurement of the inclusive W + jets cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC, with the ATLAS detector. Cross section ...
Search for Diphoton Events with Large Missing Transverse Energy with 36 pb^-1 of 7 TeV Proton-Proton Collision Data with the ATLAS Detector
Making use of 36 pb^-1 of proton-proton collision data at sqrt{s} = 7 TeV, the ATLAS Collaboration has performed a search for diphoton events with large missing transverse energy. Observing no excess of events above the Standard Model prediction, a 95% Confidence Level (CL) upper limit is set on the cross section for new physics of sigma < 0.38 - 0.65 pb in the context of a generalised model of gauge mediated supersymmetry breaking (GGM) with a bino-like lightest neutralino, and of sigma < 0.18 - 0.23 pb in the context of a specific model with one universal extra dimension (UED). A 95 % CL lower limit of 560 GeV, for bino masses above 50 GeV, is set on the GGM gluino mass, while a low…
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.
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…