LHCb

Abstract:

The decays Λb0→ ψ(2S)pK− and Λb0→ J/ψπ+π−pK−are observed in a data sample corresponding to an integrated luminosity of 3 fb^−1, collected in proton-proton collisions at 7 and 8 TeV centre-of-mass energies by the LHCb detector. The ψ(2S) mesons are reconstructed through the decay modes ψ(2S) → μ+μ−and ψ(2S) → J/ψπ+π−. The branching fractions relative to that of Λb0→ J/ψpK−are measured to be ℬ(Λb0→ψ(2S)pK−)/ℬ(Λb0→J/ψpK−) = (20.70±0.76±0.46±0.37) × 10^−2, ℬ(Λb0→ψ(2S)pK−)/ℬ(Λb0→J/ψpK−) = (20.86±0.96±1.34)×10^−2 where the first uncertainties are statistical, the second are systematic and the third is related to the knowledge of J/ψ and ψ(2S) branching fractions. The mass of the Λb0baryon is measured to be M(Λb0) = 5619.65 ± 0.17 ± 0.17MeV/c2, where the uncertainties are statistical and systematic.

Abstract:

A proton-proton collision data sample, corresponding to an integrated luminosity of 3fb−1 collected by LHCb at √s = 7 and 8 TeV, is used to reconstruct 63 ± 9 Ωb- → Ω0cπ−, Ω0c → pK−K−π+ decays. Using the Ξ−b → Ξ0cπ−, Ξ0c → pK−K−π+ decay mode for calibration, the lifetime ratio and the absolute lifetime of the Ω−b baryon are measured to be τΩ−b/τΞ−b = 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:

© 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 is performed for the charmless three-body decays of the Λb0 and Ξb0 baryons to the final states Λh+h′−, where h(′) = π or K. The analysis is based on a data sample, corresponding to an integrated luminosity of 3 fb−1 of pp collisions, collected by the LHCb experiment. The Λb0 → ΛK+π− and Λb0 → ΛK+K− decays are observed for the first time and their branching fractions and CP asymmetry parameters are measured. Evidence is seen for the Λb0 → Λπ+π− decay and limits are set on the branching fractions of Ξb0 baryon decays to the Λh+h′− final states.