Observation of the Decays Λ0b→χc1pK− and Λ0b→χc2pK−

Journal article

The first observation of the decays $Λ_{b}^{0}→χ_{c1}pK^{-}$ and $Λ_{b}^{0}→χ_{c2}pK^{-}$ is reported using a data sample corresponding to an integrated luminosity of $3.0  fb^{-1}$, collected by the LHCb experiment in $pp$ collisions at center-of-mass energies of 7 and 8 TeV. The following ratios of branching fractions are measured:

$B(Λ_{b}^{0}→χ_{c1}pK^{-})/B(Λ_{b}^{0}→J/ψpK^{-})=0.242±0.014±0.013±0.009,$ $B(Λ_{b}^{0}→χ_{c2}pK^{-})/B(Λ_{b}^{0}→J/ψpK^{-})=0.248±0.020±0.014±0.009,$ $B(Λ_{b}^{0}→χ_{c2}pK^{-})/B(Λ_{b}^{0}→χ_{c1}pK^{-})=1.02±0.10±0.02±0.05,$

where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty on the branching fractions of the $χ_{c1}→J/ψγ$ and $χ_{c2}→J/ψγ$ decays. Using both decay modes, the mass of the $Λ_{b}^{0}$ baryon is also measured to be $m_{Λ_{b}^{0}}=5619.44±0.28±0.26  MeV/c^{2}$, where the first and second uncertainties are statistical and systematic, respectively.

Authors: LHCb collaboration; Aaij, R; Adeva, B; Adinolfi, M; Harnew, N

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Physical Society
• Journal: Physical Review Letters
• Volume: 119
• Issue: 6
• Pages: 062001
• Publication date: 2017-08-08
• Acceptance date: 2017-07-12
• DOI: 10.1103/physrevlett.119.062001
• EISSN: 1079-7114
• ISSN: 0031-9007
• Pmid: 28949591
• Language: English
• Keywords: Journal Article; LHCb Collaboration