Abstract:

The direct CP asymmetries of the decays B0 → K*0μ+μ- and B+ → K+μ+μ- are measured using pp collision data corresponding to an integrated luminosity of 3.0 fb-1 collected with the LHCb detector. The respective control modes B0 → J/ψK*0 and B+ → J/ J/ψK+ are used to account for detection and production asymmetries. The measurements are made in several intervals of μ+μ- invariant mass squared, with the Ф(1020) and charmonium resonance regions excluded. Under the hypothesis of zero CP asymmetry in the control modes, the average values of the asymmetries are where the first uncertainties are statistical and the second are due to systematic effects. Both measurements are consistent with the Standard Model prediction of small CP asymmetry in these decays.

Abstract:

An angular analysis of the decay B0 → φK∗(892)0 is reported based on a pp collision data sample, corresponding to an integrated luminosity of 1.0 fb−1, collected at a centre-of-mass energy of √s = 7 TeV with the LHCb detector. The P-wave amplitudes and phases are measured with a greater precision than by previous experiments, and confirm about equal amounts of longitudinal and transverse polarization. The S-wave K+π− and K+K− contributions are taken into account and found to be significant. A comparison of the B0 → φK∗(892)0 and B0 → φK∗(892)0 results shows no evidence for direct CP violation in the rate asymmetry, in the triple-product asymmetries or in the polarization amplitudes and phases.

Abstract:

Abstract: A measurement of the inclusive W → μν production cross-section using data from pp collisions at a centre-of-mass energy of √s = 7TeV is presented. The analysis is based on an integrated luminosity of about 1.0 fb-1 recorded with the LHCb detector. Results are reported for muons with a transverse momentum greater than 20 GeV/c and pseudorapidity between 2.0 and 4.5. The W+ and W- production cross-sections are measured to be (formula presented.). where the first uncertainty is statistical, the second is systematic and the third is due to the luminosity determination. Cross-section ratios and differential distributions as functions of the muon pseudorapidity are also presented. The ratio of W+ to W- cross-sections in the same fiducial kinematic region is determined to be (formula presented.). where the uncertainties are statistical and systematic, respectively. Results are in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics.

Abstract:

© CERN 2014. All rights reserved. The production of Xb mesons in proton-proton collisions is studied using a data sample collected by the LHCb detector, at centre-of-mass energies of √s = 7 and 8TeV and corresponding to an integrated luminosity of 3.0 fb⁻¹. The Xb mesons are identified through their decays to γ(1S) and γ(2S)γ using photons that converted to e⁺e⁻ pairs in the detector. The relative prompt production rate of Xb1(1P) and Xb2(1P) mesons is measured as a function of the X(1S) transverse momentum in the Xb rapidity range 2.0 < y < 4.5. A precise measurement of the Xb(3P) mass is also performed. Assuming a mass splitting between the Xb1(3P) and the Xb2(3P) states of 10.5 MeV/c2, the measured mass of the Xb1(3P) meson is m(Xb1(3P)) = 10515.7^+2.2−3.9(stat)^+1.5−2.1(syst)MeV/c².

Abstract:

© CERN 2014. All rights reserved. The production of Xb mesons in proton-proton collisions is studied using a data sample collected by the LHCb detector, at centre-of-mass energies of √s = 7 and 8TeV and corresponding to an integrated luminosity of 3.0 fb−1. The Xb mesons are identified through their decays to γ(1S) and γ(2S)γ using photons that converted to e+e− pairs in the detector. The relative prompt production rate of Xb1(1P) and Xb2(1P) mesons is measured as a function of the X(1S) transverse momentum in the Xb rapidity range 2.0 < y < 4.5. A precise measurement of the Xb(3P) mass is also performed. Assuming a mass splitting between the Xb1(3P) and the Xb2(3P) states of 10.5 MeV/c2, the measured mass of the Xb1(3P) meson is m(Xb1(3P)) = 10515.7+2.2 −3.9(stat)+1.5 −2.1(syst)MeV/c2.