Badalov, AlexeyCalvo Gómez, MíriamCamboni, AlessandroComerma Montells, AlbertGarrido Beltrán, LluísGascón Fora, DavidGraciani Díaz, RicardoGraugés Pous, EugeniOyanguren Campos, Arantza dePérez-Calero Yzquierdo, AntonioPotterat, CédricRuiz, Hugo (Ruiz Pérez)Ruiz Valls, PabloVilasis-Cardona, XavierLHCb Collaboration2019-05-132019-05-132014-03-040031-9007https://hdl.handle.net/2445/133068Decays of ¯ B 0 s and ¯ B 0 mesons into J / ψ π + π − π + π − final states, produced in p p collisions at the LHC, are investigated using data corresponding to an integrated luminosity of 3     fb − 1 collected with the LHCb detector. ¯ B 0 ( s ) → J / ψ f 1 ( 1285 ) decays are seen for the first time, and the branching fractions are measured. Using these rates, the f 1 ( 1285 ) mixing angle between strange and nonstrange components of its wave function in the q ¯ q structure model is determined to be ± ( 24 . 0 + 3.1 + 0.6 − 2.6 − 0.8 ) ° . Implications on the possible tetraquark nature of the f 1 ( 1285 ) are discussed.9 p.application/pdfengcc by (c) CERN; LHCb Collaboration, 2014http://creativecommons.org/licenses/by/3.0/es/Física de partículesExperimentsParticle physicsExperimentsinfo:eu-repo/semantics/article6457782019-05-13info:eu-repo/semantics/openAccess