Abellan Beteta, CarlosCalvo Gómez, MíriamCamboni, AlessandroComerma Montells, AlbertDomingo Bonal, FrancescGarrido Beltrán, LluísGascón Fora, DavidGrabalosa Gándara, MarcGraciani Díaz, RicardoGraugés Pous, EugeniLópez Asamar, EliasPérez-Calero Yzquierdo, AntonioPicatoste Olloqui, EduardoPie Valls, B. (Blai)Potterat, CédricPuig Navarro, AlbertRoselló, M.Ruiz, Hugo (Ruiz Pérez)Vázquez Gómez, RicardVilasis-Cardona, XavierLHCb Collaboration2019-04-082019-04-082012-10-011550-7998https://hdl.handle.net/2445/131786A sample of 114 ± 11 B 0 s → J / ψ K − π + signal events obtained with 0.37     fb − 1 of p p collisions at √ s = 7     TeV collected by the LHCb experiment is used to measure the branching fraction and polarization amplitudes of the B 0 s → J / ψ ¯¯¯¯ K * 0 decay, with ¯¯¯¯ K * 0 → K − π + . The K − π + mass spectrum of the candidates in the B 0 s peak is dominated by the ¯¯¯¯ K * 0 contribution. Subtracting the nonresonant K − π + component, the branching fraction of B 0 s → J / ψ ¯¯¯¯ K * 0 is ( 4.4 + 0.5 − 0.4 ± 0.8 ) × 10 − 5 , where the first uncertainty is statistical and the second is systematic. A fit to the angular distribution of the decay products yields the K * 0 polarization fractions f L = 0.50 ± 0.08 ± 0.02 and f ∥ = 0.19 + 0.10 − 0.08 ± 0.02 .9 p.application/pdfengcc by (c) CERN; LHCb Collaboration, 2012http://creativecommons.org/licenses/by/3.0/es/Física de partículesExperimentsParticle physicsExperimentsinfo:eu-repo/semantics/article6196312019-04-08info:eu-repo/semantics/openAccess