© 2016 CERN. Amplitude models are applied to studies of resonance structure in D0→KS0K-π+ and D0→KS0K+π- decays using pp collision data corresponding to an integrated luminosity of 3.0 fb-1 collected by the LHCb experiment. Relative magnitude and phase information is determined, and coherence factors and related observables are computed for both the whole phase space and a restricted region of 100 MeV/c2 around the K∗(892)± resonance. Two formulations for the Kπ S-wave are used, both of which give a good description of the data. The ratio of branching fractions B(D0→KS0K+π-)/B(D0→KS0K-π+) is measured to be 0.655±0.004(stat)±0.006(syst) over the full phase space and 0.370±0.003(stat)±0.012(syst) in the restricted region. A search for CP violation is performed using the amplitude models and no significant effect is found. Predictions from SU(3) flavor symmetry for K∗(892)K amplitudes of different charges are compared with the amplitude model results.

Using a data sample of pp collisions corresponding to an integrated luminosity of 3 fb^-1, the Ξb- and Ωb- baryons are reconstructed in the Ξb-→J/ψΞ- and Ωb-→J/ψΩ- decay modes and their lifetimes measured to beτ(Ξb-)=1.55-0.09+0.10(stat)±0.03(syst)ps,τ(Ωb-)=1.54-0.21+0.26(stat)±0.05(syst)ps. These are the most precise determinations to date. Both measurements are in good agreement with previous experimental results and with theoretical predictions. © 2014 The Authors.

Using 34.7 pb−1of data collected with the LHCb detector, the inclusive production of the X(3872) meson in pp collisions at √s = 7 TeV is observed for the first time. Candidates are selected in the X(3872)→J/ψπ+π−decay mode, and used to measure σ(pp→X(3872)+anything)B(X(3872)→J/ψπ+π−) = 5.4 ± 1.3 (stat) ± 0.8 (syst) nb, where σ(pp →X(3872) + anything) is the inclusive production cross section of X(3872) mesons with rapidity in the range 2.5–4.5 and transverse momentum in the range 5–20 GeV/c. In addition the masses of both the X(3872) and ψ(2S) mesons, reconstructed in the J/ψπ+π−final state, are measured to be mX(3872) = 3871.95 ± 0.48 (stat) ± 0.12 (syst) MeV/c2and mψ(2S) = 3686.12± 0.06 (stat) ± 0.10 (syst) MeV/c2.

© (publication year), (publisher). All rights reserved. A search for CP violation using T-odd correlations is performed using the four-body D0→ K+K-π+π−decay, selected from semileptonic B decays. The data sample corresponds to integrated luminosities of 1.0 fb-1and 2.0 fb-1recorded at the centre-of-mass energies of 7TeV and 8TeV, respectively. The CP-violating asymmetry (Formula presented.) is measured to be (0.18 ± 0.29 (stat) ± 0.04 (syst))%. Searches for CP violation in different regions of phase space of the four-body decay, and as a function of the D0decay time, are also presented. No significant deviation from the CP conservation hypothesis is found.

A search for the rare decay D0→μ+μ- is performed using a data sample, corresponding to an integrated luminosity of 0.9fb-1, of pp collisions collected at a centre-of-mass energy of 7 TeV by the LHCb experiment. The observed number of events is consistent with the background expectations and corresponds to an upper limit of B(D0→μ+μ-)<6.2(7.6)×10-9 at 90% (95%) confidence level. This result represents an improvement of more than a factor twenty with respect to previous measurements. © 2013 CERN.

© 2014 The Authors. A search for time-integrated CP violation in the Cabibbo-suppressed decay D0→π-π+π0is performed using for the first time an unbinned model-independent technique known as the energy test. Using proton-proton collision data, corresponding to an integrated luminosity of 2.0fb-1collected by the LHCb detector at a centre-of-mass energy of s=8TeV, the world's best sensitivity to CP violation in this decay is obtained. The data are found to be consistent with the hypothesis of CP symmetry with a p-value of (2.6±0.5)%.

The production of J/ψ mesons in proton-proton collisions at √S = 7 TeV is studied with the LHCb detector at the LHC. The differential cross-section for prompt J/ψ production is measured as a function of the J/ψ transverse momentum pT and rapidity y in the fiducial region pT ∈ [0; 14] GeV/c and y ∈ [2.0; 4.5]. The differential cross-section and fraction of J/ψ from b-hadron decays are also measured in the same pT and y ranges. The analysis is based on a data sample corresponding to an integrated luminosity of 5.2 pb^&-1. The measured cross-sections integrated over the fiducial region are 10.52 ± 0.04 ± 1.40^+1.64 &-2.20 μb for prompt J/ψ production and 1.14 ± 0.01 ± 0.16 μb for J/ψ from b-hadron decays, where the first uncertainty is statistical and the second systematic. The prompt J/ψ production cross-section is obtained assuming no J/ψ polarisation and the third error indicates the acceptance uncertainty due to this assumption.

© 2015 Article funded by SCOAP3 and published under licence by Chinese Physical Society. The product of the Λ0b(B0) differential production cross-section and the branching fraction of the decay Λ0bJ= pK.. (B0!J= K Λ (892)0) is measured as a function of the beauty hadron transverse momentum, pT, and rapidity, y. The kinematic region of the measurements is pT >20 GeV=c and 2:0>y>4:5. The measurements use a data sample corresponding to an integrated luminosity of 3fb..1 collected by the LHCb detector in pp collisions at centre-of-mass energies ps = 7 TeV in 2011 and ps = 8 TeV in 2012. Based on previous LHCb results of the fragmentation fraction ratio, fΛ0 b =fd, the branching fraction of the decay Λ0 b!J= pK.. is measured to be B(Λ0 bJ= pK..)=(3:17±0:04±0:07±0:34+0:45 ..0:28 )10..4 ; where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay B0J= K Λ (892)0, and the fourth is due to the knowledge of fΛ0 b =fd. The sum of the asymmetries in the production and decay between Λ0 b and Λ 0 b is also measured as a function of pT and y. The previously published branching fraction of Λ0 b ! J= p.., relative to that of Λ0 b ! J= pK.., is updated. The branching fractions of Λ0 b!P+ c (!J= p)K.. are determined.

© 2012, CERN for the benefit of the LHCb collaboration. The charged−particle production ratios p/p, K −/K +, π −/π +, (p + p)/(π ++π −), (K ++K −)/(π + + π −) and (p+ p)/(K + + K −) are measured with the LHCb detector using 0.3 nb−1 of pp collisions delivered by the LHC at √s = 0.9 TeV and 1.8 nb−1 at √s = 7 TeV. The measurements are performed as a function of transverse momentum pT and pseudorapidity η. The production ratios are compared to the predictions of several Monte Carlo generator settings, none of which are able to describe adequately all observables. The ratio p/p is also considered as a function of rapidity loss, Δy ≡ ybeam − y, and is used to constrain models of baryon transport.

© 2015 CERN for the LHCb Collaboration. Published by the American Physical Society. We report a study of the suppressed B-→DK-π+π- and favored B-→Dπ-π+π- decays, where the neutral D meson is detected through its decays to the K π± and CP -even K+K- and π+π- final states. The measurement is carried out using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 3.0 fb-1. We observe the first significant signals in the CP -even final states of the D meson for both the suppressed B-→DK-π+π- and favored B-→Dπ-π+π- modes, as well as in the doubly Cabibbo suppressed D→K+π- final state of the B-→Dπ-π+π- decay. Evidence for the suppressed decay B-→DK-π+π-, with D→K+π-, is also presented. From the observed yields in the B-→DK-π+π-, B-→Dπ-π+π- and their charge conjugate decay modes, the most probable value of the weak phase γ corresponds to γ=(74-19+20)°. This is one of the most precise single-measurement determinations of γ to date.