The first observation of the decays Λb0→χc1pK- and Λb0→χc2pK- 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(Λb0→χc1pK-)B(Λb0→J/ψpK-)=0.242±0.014±0.013±0.009,B(Λb0→χc2pK-)B(Λb0→J/ψpK-)=0.248±0.020±0.014±0.009,B(Λb0→χc2pK-)B(Λb0→χc1pK-)=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 χc1→J/ψγ and χc2→J/ψγ decays. Using both decay modes, the mass of the Λb0 baryon is also measured to be mΛb0=5619.44±0.28±0.26 MeV/c2, where the first and second uncertainties are statistical and systematic, respectively.
Aaij, R., Adeva, B., Adinolfi, M., Ajaltouni, Z., Akar, S., Albrecht, J., et al. (2017). Observation of the Decays Λ0b → χ c1pK − and Λ0b → χ c2pK −. PHYSICAL REVIEW LETTERS, 119(6) [10.1103/PhysRevLett.119.062001].
Observation of the Decays Λ0b → χ c1pK − and Λ0b → χ c2pK −
Belloli, N.;Borgheresi, A.;Borsato, M.;Calvi, M.;Carniti, P.;Cassina, L.;Fazzini, D.;Gotti, C.
;Grillo, L.;Martinelli, M.;Matteuzzi, C.;Petruzzo, M.;
2017
Abstract
The first observation of the decays Λb0→χc1pK- and Λb0→χc2pK- 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(Λb0→χc1pK-)B(Λb0→J/ψpK-)=0.242±0.014±0.013±0.009,B(Λb0→χc2pK-)B(Λb0→J/ψpK-)=0.248±0.020±0.014±0.009,B(Λb0→χc2pK-)B(Λb0→χc1pK-)=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 χc1→J/ψγ and χc2→J/ψγ decays. Using both decay modes, the mass of the Λb0 baryon is also measured to be mΛb0=5619.44±0.28±0.26 MeV/c2, where the first and second uncertainties are statistical and systematic, respectively.
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