Abstract: The decays Λ b 0→ ψ(2S)pK −and Λ b 0→ 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 Λ b 0→ J/ψpK −are measured to beℬ(Λ b 0→ψ(2S)pK −)/ℬ(Λ b 0→J/ψpK −)=(20.70±0.76±0.46±0.37)×10 −2, ℬ(Λ b 0→ψ(2S)pK −)/ℬ(Λ b 0→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 Λ b 0baryon is measured to be M(Λ b 0)=5619.65±0.17±0.17MeV/c 2, where the uncertainties are statistical and systematic.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics