Calvo Gómez, MíriamCamboni, AlessandroComerma Montells, AlbertGarrido Beltrán, LluísGraciani Díaz, RicardoGraugés Pous, EugeniOyanguren Campos, Arantza dePérez-Calero Yzquierdo, AntonioPicatoste Olloqui, EduardoPotterat, CédricRives Molina, Vicente JoséRuiz, Hugo (Ruiz Pérez)Ruiz Valls, PabloVilasis-Cardona, XavierLHCb Collaboration2019-05-162019-05-162013-09-100031-9007https://hdl.handle.net/2445/133326A broad peaking structure is observed in the dimuon spectrum of B + → K + μ + μ − decays in the kinematic region where the kaon has a low recoil against the dimuon system. The structure is consistent with interference between the B + → K + μ + μ − decay and a resonance and has a statistical significance exceeding six standard deviations. The mean and width of the resonance are measured to be 4191 + 9 − 8     MeV / c 2 and 65 + 22 − 16     MeV / c 2 , respectively, where the uncertainties include statistical and systematic contributions. These measurements are compatible with the properties of the ψ ( 4160 ) meson. First observations of both the decay B + → ψ ( 4160 ) K + and the subsequent decay ψ ( 4160 ) → μ + μ − are reported. The resonant decay and the interference contribution make up 20% of the yield for dimuon masses above 3770     MeV / c 2 . This contribution is larger than theoretical estimates.8 p.application/pdfengcc by (c) CERN; LHCb Collaboration, 2013http://creativecommons.org/licenses/by/3.0/es/Física de partículesExperimentsParticle physicsExperimentsinfo:eu-repo/semantics/article6290282019-05-16info:eu-repo/semantics/openAccess