Decays of B0 and B0s mesons to the charmless baryonic final states p¯ph+h'–, where h and h' each denote a kaon or a pion, are searched for using the LHCb detector. The analysis is based on a sample ...of proton-proton collision data collected at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb–1. Four-body charmless baryonic B0s decays are observed for the first time. The decays B0s→p¯pK+K–, B0s→p¯pK±π∓, B0→p¯pK±π∓ and B0→p¯pπ+π– are observed with a significance greater than 5 standard deviations; evidence at 4.1 standard deviations is found for the B0→p¯pK+K– decay and an upper limit is set on the branching fraction for B0s→p¯pπ+π–. Branching fractions in the kinematic region m(p¯p) < 2850 MeV/c2 are measured relative to the B0→J/ψ(→p¯p)K*(892)0 channel.
Measurements of $B_c^+$ production and mass are performed with the decay mode $B_c^+ \to J/\psi \pi^+$ using 0.37 fb$^{-1}$ of data collected in $pp$ collisions at $\sqrt{s}=7$ TeV by the LHCb ...experiment. The ratio of the production cross-section times branching fraction between the $B_c^+ \to J/\psi \pi^+$ and the $B^+ \to J/\psi K^+$ decays is measured to be $(0.68 \pm 0.10\,({\rm stat.}) \pm 0.03\,({\rm syst.}) \pm 0.05\,({\rm lifetime}))%$ for $B_c^+$ and $B^+$ mesons with transverse momenta $p_{\rm T}>4 $GeV/$c$ and pseudorapidities $2.5<\eta<4.5$. The $B_c^+$ mass is directly measured to be $6273.7 \pm 1.3\,({\rm stat.}) \pm 1.6 \,({\rm syst.})$ MeV/$c^2$, and the measured mass difference with respect to the $B^+$ meson is $M(B_c^+)-M(B^+) = 994.6 \pm 1.3\,({\rm stat.}) \pm 0.6\,({\rm syst.})$ MeV/$c^2$.
Abstract A combination of measurements sensitive to the CKM angle γ from LHCb is performed. The inputs are from analyses of time-integrated B + arrow right DK +, B 0 arrow right DK 0, B 0 arrow right ...DK +pi- and B + arrow right DK +pi+pi- tree-level decays. In addition, results from a time-dependent analysis of B s 0 arrow rightD s K ± decays are included. The combination yields γ=(72.2 -7.3 +6.8 )°, where the uncertainty includes systematic effects. The 95.5% confidence level interval is determined to be γ 55.9, 85.2°. A second combination is investigated, also including measurements from B + arrow right Dpi+ and B + arrow right Dpi+pi-pi+ decays, which yields compatible results. Figure not available: see fulltext.
Violations of CPT symmetry and Lorentz invariance are searched for by studying interference effects in B^{0} mixing and in B_{s}^{0} mixing. Samples of B^{0}→J/ψK_{S}^{0} and B_{s}^{0}→J/ψK^{+}K^{-} ...decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb^{-1}. No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and CPT symmetry. Results are expressed in terms of the standard model extension parameter Δa_{μ} with precisions of O(10^{-15}) and O(10^{-14}) GeV for the B^{0} and B_{s}^{0} systems, respectively. With no assumption on Lorentz (non)invariance, the CPT-violating parameter z in the B_{s}^{0} system is measured for the first time and found to be Re(z)=-0.022±0.033±0.005 and Im(z)=0.004±0.011±0.002, where the first uncertainties are statistical and the second systematic.
The decays Formula: see text and Formula: see text are observed for the first time using a data sample corresponding to an integrated luminosity of 3.0 fbFormula: see text, collected by the LHCb ...experiment in proton-proton collisions at the centre-of-mass energies of 7 and 8Formula: see text. The branching fractions relative to that of Formula: see text are measured to be Formula: see textwhere the first uncertainties are statistical and the second are systematic.
Two new algorithms for use in the analysis of Formula: see text collision are developed to identify the flavour of Formula: see text mesons at production using pions and protons from the ...hadronization process. The algorithms are optimized and calibrated on data, using Formula: see text decays from Formula: see text collision data collected by LHCb at centre-of-mass energies of 7 and 8 TeV . The tagging power of the new pion algorithm is 60% greater than the previously available one; the algorithm using protons to identify the flavour of a Formula: see text meson is the first of its kind.
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