5 research outputs found

    Measurement of the flavour-specific CP-violating asymmetry as sl in B0s decays

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    The CP  -violating asymmetry is studied using semileptonic decays of and mesons produced in pp   collisions at a centre-of-mass energy of 7 TeV at the LHC, exploiting a data sample corresponding to an integrated luminosity of 1.0 fb−1. The reconstructed final states are , with the particle decaying in the ϕπ± mode. The yields are summed over and initial states, and integrated with respect to decay time. Data-driven methods are used to measure efficiency ratios. We obtain , where the first uncertainty is statistical and the second systematic

    Searches for violation of lepton flavour and baryon number in tau lepton decays at LHCb

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    Searches for the lepton flavour violating decay τ−→μ−μ+μ−τ−→μ−μ+μ− and the lepton flavour and baryon number violating decays sourceτ−→p¯μ+μ− and τ−→pμ−μ−τ−→pμ−μ− have been carried out using proton–proton collision data, corresponding to an integrated luminosity of 1.0 fb−11.0 fb−1, taken by the LHCb experiment at s=7 TeV. No evidence has been found for any signal, and limits have been set at 90%90% confidence level on the branching fractions: B(τ−→μ−μ+μ−)<8.0×10−8B(τ−→μ−μ+μ−)<8.0×10−8, B(τ−→p¯μ+μ−)<3.3×10−7 and B(τ−→pμ−μ−)<4.4×10−7B(τ−→pμ−μ−)<4.4×10−7. The results for the τ−→p¯μ+μ− and τ−→pμ−μ−τ−→pμ−μ− decay modes represent the first direct experimental limits on these channels

    Observation of B[0s χc1φ decay and study of: B0 -> χ c1,2K*1 decays

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    The first observation of the decay B0s → χc1φ and a study of B0 → χc1,2K*0 decays are presented. The analysis is performed using a dataset, corresponding to an integrated luminosity of 1.0 fb-1, collected by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. The following ratios of branching fractions are measured: Where the third uncertainty is due to the limited knowledge of the branching fractions of χc → J/ψγ modes. © 2013 CERN. Published by Elsevier B.V

    Search for direct CP violation in D0 -> h- h+ modes using semileptonic B decays

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    15 pages, 4 figures - See paper for full list of authorsA search for direct CP violation in D0 -> h- h+ (where h=K or pi) is presented using data corresponding to an integrated luminosity of 1.0 fb^-1 collected in 2011 by LHCb in pp collisions at a centre-of-mass energy of 7 TeV. The analysis uses D0 mesons produced in inclusive semileptonic b-hadron decays to the D0 mu X final state, where the charge of the accompanying muon is used to tag the flavour of the D0 meson. The difference in the CP-violating asymmetries between the two decay channels is measured to be Delta A_CP = A_CP(K-K+) - A_CP(pi-pi+) = (0.49 +- 0.30 (stat) +- 0.14 (syst)) % . This result does not confirm the evidence for direct CP violation in the charm sector reported in other analyses

    Search for the rare decay D0μ+μD^0 \to \mu^+ \mu^-

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    22 pages, 8 figures, Submitted to Physics Letters BA search for the rare decay D0μ+μD^0 \to \mu^+ \mu^-is performed using a data sample, corresponding to an integrated luminosity of 0.9 fb1^{-1}, of pppp 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 \mbox{B(D0μ+μ)<6.2(7.6)×109{\cal B}(D^0 \to \mu^+ \mu^-) < 6.2(7.6) \times 10^{-9}} at \mbox{90%} \mbox{(95%)} confidence level. This result represents an improvement of more than a factor twenty with respect to previous measurements
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