Observation of the Λ0b → J/ψ pπ- Decay

The LHCb Collaboration

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The first observation of the Cabibbo-suppressed decay Λ b → J/ψpπ is reported using a data sample of proton-proton collisions at 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb-1. A prominent signal is observed and the branching fraction relative to the decay mode Λ b → J/ψpK is determined to be B (Λb → J / ψp π-/ B Λ b → J / ψp K- = 0.0824 ± 0.0025 stat ± 0.0042 syst. A search for direct CP violation is performed. The difference in the CP asymmetries between these two decays is found to be A CP (Λb → J / ψp π-) - A CP (Λb → J / ψp K-) = + 5.7 ± 2.4 stat ± 1.2 syst %, which is compatible with CP symmetry at the 2.2σ level.
Original languageEnglish
Article number103
Number of pages19
JournalJournal of High Energy Physics
Issue number7
Publication statusPublished - 2014
Externally publishedYes


  • B physics
  • CP violation
  • Branching fraction
  • Flavor physics
  • Hadron-Hadron Scattering

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