Observation of Λb0 → ψ(2S)pK− and Λb0→ J/ψ π+ π− pK- decays and a measurement of the Λb0 baryon mass

Journal article

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.

Authors: Cheung, S; Evans, T; Gandini, P; Hadavizadeh, T; Harnew, N

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: Journal of High Energy Physics
• Volume: 2016
• Issue: 5
• Pages: 132
• Publication date: 2016-05-23
• Acceptance date: 2016-05-09
• DOI: 10.1007/JHEP05(2016)132
• ISSN: 1126-6708 and 1029-8479
• Keywords: Spectroscopy; Flavor physics; Hadron-Hadron scattering (experiments); Particle and resonance production; B physics