Model-independent evidence for J/ψpJ/\psi p contributions to Λb0→J/ψpK−\Lambda_b^0\to J/\psi p K^- decays

The data sample of $\Lambda_b^0\to J/\psi p K^-$ decays acquired with the LHCb detector from 7 and 8~TeV $pp$ collisions, corresponding to an integrated luminosity of 3 fb$^{-1}$, is inspected for the presence of $J/\psi p$ or $J/\psi K^-$ contributions with minimal assumptions about $K^- p$ contributions. It is demonstrated at more than 9 standard deviations that $\Lambda_b^0\to J/\psi p K^-$ decays cannot be described with $K^- p$ contributions alone, and that $J/\psi p$ contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for $P_c^+\to J/\psi p$ charmonium-pentaquark states in the same data sample.Comment: 21 pages, 12 figures (including the supplemental section added at the end

Quantum numbers of the X(3872)X(3872) state and orbital angular momentum in its ρ0Jψ\rho^0 J\psi decay

Angular correlations in $B^+\to X(3872) K^+$ decays, with $X(3872)\to \rho^0 J/\psi$, $\rho^0\to\pi^+\pi^-$ and $J/\psi \to\mu^+\mu^-$, are used to measure orbital angular momentum contributions and to determine the $J^{PC}$ value of the $X(3872)$ meson. The data correspond to an integrated luminosity of 3.0 fb$^{-1}$ of proton-proton collisions collected with the LHCb detector. This determination, for the first time performed without assuming a value for the orbital angular momentum, confirms the quantum numbers to be $J^{PC}=1^{++}$. The $X(3872)$ is found to decay predominantly through S wave and an upper limit of $4\%$ at $95\%$ C.L. is set on the fraction of D wave.Comment: 16 pages, 4 figure

Measurement of the Bs0→J/ψK∗0B^0_s\rightarrow J/\psi K^{*0} branching fraction and angular amplitudes

A search for the decay $B^0_s\rightarrow J/\psi K^{*0}$ with $K^{*0} \rightarrow K^-\pi^+$ is performed with 0.37 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 7 TeV collected by the LHCb experiment, finding a \Bs \to J\psi K^-\pi^+ peak of $114 \pm 11$ signal events. The $K^-\pi^+$ mass spectrum of the candidates in the $B^0_s$ peak is dominated by the $K^{*0}$ contribution. Subtracting the non-resonant $K^-\pi^+$ component, the branching fraction of \BsJpsiKst is $(4.4_{-0.4}^{+0.5} \pm 0.8) \times 10^{-5}$, where the first uncertainty is statistical and the second systematic. A fit to the angular distribution of the decay products yields the \Kst polarization fractions $f_L = 0.50 \pm 0.08 \pm 0.02$ and $f_{||} = 0.19^{+0.10}_{-0.08} \pm 0.02$

Measurement of Upsilon production in pp collisions at \sqrt{s} = 7 TeV

The production of Upsilon(1S), Upsilon(2S) and Upsilon(3S) mesons in proton-proton collisions at the centre-of-mass energy of sqrt(s)=7 TeV is studied with the LHCb detector. The analysis is based on a data sample of 25 pb-1 collected at the Large Hadron Collider. The Upsilon mesons are reconstructed in the decay mode Upsilon -> mu+ mu- and the signal yields are extracted from a fit to the mu+ mu- invariant mass distributions. The differential production cross-sections times dimuon branching fractions are measured as a function of the Upsilon transverse momentum pT and rapidity y, over the range pT < 15 GeV/c and 2.0 < y < 4.5. The cross-sections times branching fractions, integrated over these kinematic ranges, are measured to be sigma(pp -> Upsilon(1S) X) x B(Upsilon(1S)->mu+ mu-) = 2.29 {\pm} 0.01 {\pm} 0.10 -0.37 +0.19 nb, sigma(pp -> Upsilon(2S) X) x B(Upsilon(2S)->mu+ mu-) = 0.562 {\pm} 0.007 {\pm} 0.023 -0.092 +0.048 nb, sigma(pp -> Upsilon(3S) X) x B(Upsilon(3S)->mu+ mu-) = 0.283 {\pm} 0.005 {\pm} 0.012 -0.048 +0.025 nb, where the first uncertainty is statistical, the second systematic and the third is due to the unknown polarisation of the three Upsilon states.Comment: 22 pages, 7 figure

Evidence for CP violation in time-integrated D0 -> h-h+ decay rates

A search for time-integrated CP violation in D0 -> h-h+ (h=K, pi) decays is presented using 0.62 fb^-1 of data collected by LHCb in 2011. The flavor of the charm meson is determined by the charge of the slow pion in the D*+ -> D0 pi+ and D*- -> D0bar pi- decay chains. The difference in CP asymmetry between D0 -> K-K+ and D0 -> pi-pi+, Delta ACP = ACP(K-K+) - ACP(pi-pi+), is measured to be [-0.82 \pm 0.21(stat.) \pm 0.11(syst.)]%. This differs from the hypothesis of CP conservation by 3.5 standard deviations.Comment: 8 pages, 3 figures, 2 tables; v2 minor updates after journal revie

Measurement of CP violation and constraints on the CKM angle γ in B± → DK± with D → K0Sπ+π− decays

A model-dependent amplitude analysis of B± → DK± with D → K0 Sπ+π− decays is performed using proton–proton collision data, corresponding to an integrated luminosity of 1 fb−1, recorded by LHCb at a centre-of-mass energy of 7 TeV in 2011. Values of the CP violation observables x± and y±, which are sensitive to the CKM angle γ, are measured to be x− = +0.027 ± 0.044+0.010 −0.008 ± 0.001, y− = +0.013 ± 0.048+0.009 −0.007 ± 0.003, x+ = −0.084 ± 0.045 ± 0.009 ± 0.005, y+ = −0.032 ± 0.048+0.010 −0.009 ± 0.008, where the first uncertainty is statistical, the second systematic and the third arises from the uncertainty of the D → K0 Sπ+π− amplitude model. The value of γ is determined to be (84+49 −42)◦, including all sources of uncertainty. Neutral D meson mixing is found to have negligible effect

Measurement of relative branching fractions of B decays to psi(2S) and J/psi mesons

The relative rates of B-meson decays into J/psi and psi(2S) mesons are measured for the three decay modes in pp collisions recorded with the LHCb detector. The ratios of branching fractions (B) are measured to be B(B+ -> psi(2S)K+)/B(B+ -> J/psi K+) = 0.594 +/- 0.006(stat) +/- 0.016(syst) +/- 0.015(R-psi), B(B-0 -> psi(2S)K*(0))/B(B-0 -> J/psi K*(0)) = 0.476 +/- 0.014(stat) +/- 0.010(syst) +/- 0.012(R-psi), B(B-s(0) -> psi(2S)phi)/B(B-s(0) -> J/psi phi) = 0.489 +/- 0.026(stat) +/- 0.021(syst) +/- 0.012(R-psi), where the third uncertainty is from the ratio of the psi(2S) and J/psi branching fractions to mu(+)mu(-). RI Galli, Domenico/A-1606-2012; Sarti, Alessio/I-2833-2012; Petrolini, Alessandro/H-3782-2011; Carbone, Angelo/C-8289-2012; de Paula, Leandro/I-9278-2012; manca, giulia/I-9264-2012; Patrignani, Claudia/C-5223-2009; Marconi, Umberto/J-2263-2012; de Simone, Patrizia/J-3549-2012; Cardini, Alessandro/J-5736-2012; Teodorescu, Eliza/K-3044-201

Precision measurement of the ratio of the Lambda(0)(b) to (B)over-bar(0) lifetimes

The LHCb measurement of the lifetime ratio of the Lambda(0)(b) baryon to the (B) over bar (0) meson is updated using data corresponding to an integrated luminosity of 3.0 fb(-1) collected using 7 and 8 TeV centre-of-mass energy pp collisions at the LHC. The decay modes used are Lambda(0)(b) -> J/psi pK(-) and (B) over bar (0) -> J/psi pi K-+(-), where the pi K-+(-) mass is consistent with that of the (K) over bar*(0)(892) meson. The lifetime ratio is determined with unprecedented precision to be 0.974 +/- 0.006 +/- 0.004, where the first uncertainty is statistical and the second systematic. This result is in agreement with original theoretical predictions based on the heavy quark expansion. Using the current world average of the (B) over bar (0) lifetime, the Lambda(0)(b) lifetime is found to be 1.479 +/- 0.009 +/- 0.010 ps

Precision measurement of the ratio of the Lambda(0)(b) to (B)over-bar(0) lifetimes

The LHCb measurement of the lifetime ratio of the Lambda(0)(b) baryon to the (B) over bar (0) meson is updated using data corresponding to an integrated luminosity of 3.0 fb(-1) collected using 7 and 8 TeV centre-of-mass energy pp collisions at the LHC. The decay modes used are Lambda(0)(b) -> J/psi pK(-) and (B) over bar (0) -> J/psi pi K-+(-), where the pi K-+(-) mass is consistent with that of the (K) over bar*(0)(892) meson. The lifetime ratio is determined with unprecedented precision to be 0.974 +/- 0.006 +/- 0.004, where the first uncertainty is statistical and the second systematic. This result is in agreement with original theoretical predictions based on the heavy quark expansion. Using the current world average of the (B) over bar (0) lifetime, the Lambda(0)(b) lifetime is found to be 1.479 +/- 0.009 +/- 0.010 ps. (C) 2014 The Authors. Published by Elsevier B.V