Alfonso Albero, AlejandroGarcía Moreno, PaulaGarrido Beltrán, LluísGironella Gironell, P.Gomez Fernandez, S.Graugés Pous, EugeniLobo Salvia, A.Mauricio, J.Vazquez Gomez, R.Marin Benito, CarlaLHCb Collaboration2022-05-102022-05-1020211126-6708https://hdl.handle.net/2445/185486The Cabibbo-suppressed decay Λ 0 b → χc1pπ − is observed for the first time using data from proton-proton collisions corresponding to an integrated luminosity of 6 fb−1 , collected with the LHCb detector at a centre-of-mass energy of 13 TeV. Evidence for the Λ 0 b → χc2pπ − decay is also found. Using the Λ 0 b → χc1pK− decay as normalisation channel, the ratios of branching fractions are measured to be B Λ 0 b → χc1pπ − B Λ0 b → χc1pK− = (6.59 ± 1.01 ± 0.22) × 10−2 , B Λ 0 b → χc2pπ − B Λ0 b → χc1pπ− = 0.95 ± 0.30 ± 0.04 ± 0.04 , B Λ 0 b → χc2pK− B Λ0 b → χc1pK− = 1.06 ± 0.05 ± 0.04 ± 0.04 , where the first uncertainty is statistical, the second is systematic and the third is due to the uncertainties in the branching fractions of χc1,2 → J/ψγ decays. Keywords: B physics, Branching fraction, Hadron-Hadron scattering (experiments), QCD, Quar21 p.application/pdfengcc-by (c) Alfonso Albero, Alejandro et al., 2021https://creativecommons.org/licenses/by/4.0/HadronsGran Col·lisionador d'HadronsFísica de partículesExperimentsHadronsLarge Hadron Collider (France and Switzerland)Particle physicsExperimentsinfo:eu-repo/semantics/article7210752022-05-10info:eu-repo/semantics/openAccess