Badalov, AlexeyCalvo Gómez, MíriamCamboni, AlessandroCoquereau, SamuelFernandez, G.Garrido Beltrán, LluísGascón Fora, DavidGraciani Díaz, RicardoGraugés Pous, EugeniMarin Benito, CarlaPicatoste Olloqui, EduardoRives Molina, Vicente JoséSánchez Gonzalo, DavidVilasis-Cardona, XavierLHCb Collaboration2019-05-062019-05-062017-08-080031-9007https://hdl.handle.net/2445/132724The first observation of the decays Λb0→χc 1p K- and Λb0→χc 2p K- is reported using a data sample corresponding to an integrated luminosity of 3.0 fb-1, collected by the LHCb experiment in p p collisions at center-of-mass energies of 7 and 8 TeV. The following ratios of branching fractions are measured: B/(Λb0→χc 1p K-) B (Λb0→J /ψ p K-) =0.242 ±0.014 ±0.013 ±0.009 ,B/(Λb0→χc 2p K-) B (Λb0→J /ψ p K-) =0.248 ±0.020 ±0.014 ±0.009 ,B/(Λb0→χc 2p K-) B (Λb0→χc 1p K-) =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 χc 1→J /ψ γ and χc 2→J /ψ γ 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.11 p.application/pdfengcc by (c) CERN; LHCb Collaboration, 2017http://creativecommons.org/licenses/by/3.0/es/Física de partículesExperimentsParticle physicsExperimentsinfo:eu-repo/semantics/article6780122019-05-06info:eu-repo/semantics/openAccess