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Abstract:

© 2016 CERN, for the LHCb Collaboration. Published by the American Physical Society under the terms of the "http://creativecommons.org/licenses/by/3.0/" Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. The branching fraction of the decay Bs0→Ds(∗)+Ds(∗)- is measured using pp collision data corresponding to an integrated luminosity of 1.0 fb-1, collected using the LHCb detector at a center-of-mass energy of 7 TeV. It is found to be B(Bs0→Ds(∗)+Ds(∗)-)=(3.05±0.10±0.20±0.34)%, where the uncertainties are statistical, systematic, and due to the normalization channel, respectively. The branching fractions of the individual decays corresponding to the presence of one or two Ds∗± are also measured. The individual branching fractions are found to be B(Bs0→Ds∗±Dsℓ)=(1.35±0.06±0.09±0.15)%, B(Bs0→Ds∗+Ds∗-)=(1.27±0.08±0.10±0.14)%. All three results are the most precise determinations to date.

Abstract:

© 2016 CERN, for the LHCb Collaboration. Published by the American Physical Society under the terms of the http://creativecommons.org/licenses/by/3.0/ Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.A proton-proton collision data sample, corresponding to an integrated luminosity of 3 fb-1 collected by LHCb at s=7 and 8 TeV, is used to reconstruct 63±9 Ωb-→Ωc0π-, Ωc0→pK-K-π+ decays. Using the Ξb-→Ξc0π-, Ξc0→pK-K-π+ decay mode for calibration, the lifetime ratio and the absolute lifetime of the Ωb- baryon are measured to be τΩb-/τΞb-=1.11±0.16±0.03, τΩb-=1.78±0.26±0.05±0.06 ps, where the uncertainties are statistical, systematic and from the calibration mode (for τΩb- only). A measurement is also made of the mass difference, mΩb - mΞb-, and the corresponding Ωb- mass, which yields mΩb - mΞb-=247.4±3.2±0.5 MeV/c2, mΩb-=6045.1±3.2±0.5±0.6 MeV/c2. These results are consistent with previous measurements.

Abstract:

A search for CP violation in D^{0}→K^{-}K^{+} and D^{0}→π^{-}π^{+} decays is performed using pp collision data, corresponding to an integrated luminosity of 3  fb^{-1}, collected using the LHCb detector at center-of-mass energies of 7 and 8 TeV. The flavor of the charm meson is inferred from the charge of the pion in D^{*+}→D^{0}π^{+} and D^{*-}→D[over ¯]^{0}π^{-} decays. The difference between the CP asymmetries in D^{0}→K^{-}K^{+} and D^{0}→π^{-}π^{+} decays, ΔA_{CP}≡A_{CP}(K^{-}K^{+})-A_{CP}(π^{-}π^{+}), is measured to be [-0.10±0.08(stat)±0.03(syst)]%. This is the most precise measurement of a time-integrated CP asymmetry in the charm sector from a single experiment.

Abstract:

We perform a search for near-threshold Ξb0 resonances decaying to Ξb−π+ in a sample of proton-proton collision data corresponding to an integrated luminosity of 3 fb−1 collected by the LHCb experiment. We observe one resonant state, with the following properties: m(Ξ∗0b) − m(Ξ−b) − m(π+) = 15.727 ± 0.068(stat) ± 0.023(syst) MeV/c2 Γ(Ξ∗0b) = 0.90 ± 0.16(stat) ± 0.08(syst) MeV. This confirms the previous observation by the CMS collaboration. The state is consistent with the JP = 3/2+  Ξb∗ 0 resonance expected in the quark model. This is the most precise determination of the mass and the first measurement of the natural width of this state. We have also measured the ratio σ(pp→Ξ∗0bX)B(Ξ∗0b→Ξ−bπ+)/σ(pp → Ξ−bX) =0.28 ± 0.03(stat.) ± 0.01(syst.).