2026-04-17T22:54:31Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1324962025-12-04T21:29:19Zcom_2072_1057col_2072_478812col_2072_478823col_2072_478904col_2072_478917

Measurement of the Ratio of Branching Fractions B (Bc+ →j /ψτ+ντ)/ B (Bc+ →j /ψμ+νμ) Alfonso Albero, Alejandro Badalov, Alexey Calvo Gómez, Míriam Camboni, Alessandro Coquereau, Samuel Fernandez, G. Garrido Beltrán, Lluís Gascón Fora, David Graciani Díaz, Ricardo Graugés Pous, Eugeni Marin Benito, Carla Picatoste Olloqui, Eduardo Rives Molina, Vicente José Vilasis-Cardona, Xavier LHCb Collaboration Física de partícules Experiments Particle physics Experiments A measurement is reported of the ratio of branching fractions R ( J / ψ ) = B ( B + c → J / ψ τ + ν τ ) / B ( B + c → J / ψ μ + ν μ ) , where the τ + lepton is identified in the decay mode τ + → μ + ν μ ¯ ν τ . This analysis uses a sample of proton-proton collision data corresponding to 3.0     fb − 1 of integrated luminosity recorded with the LHCb experiment at center-of-mass energies of 7 and 8 TeV. A signal is found for the decay B + c → J / ψ τ + ν τ at a significance of 3 standard deviations corrected for systematic uncertainty, and the ratio of the branching fractions is measured to be R ( J / ψ ) = 0.71 ± 0.17 ( stat ) ± 0.18 ( syst ) . This result lies within 2 standard deviations above the range of central values currently predicted by the standard model. 2019-04-29T09:46:13Z 2019-04-29T09:46:13Z 2018-03-23 2019-04-29T09:46:13Z info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 0031-9007 https://hdl.handle.net/2445/132496 684707 eng Reproducció del document publicat a: https://doi.org/10.1103/PhysRevLett.120.121801 Physical Review Letters, 2018, vol. 120, num. 12, p. 121801 https://doi.org/10.1103/PhysRevLett.120.121801 cc by (c) CERN; LHCb Collaboration, 2018 http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess 10 p. application/pdf American Physical Society Articles publicats en revistes (Física Quàntica i Astrofísica)