2026-04-13T13:32:07Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1328722025-12-04T21:28:07Zcom_2072_1057col_2072_478812col_2072_478823col_2072_478904col_2072_478917

RECERCAT author Badalov, Alexey author Calvo Gómez, Míriam author Garrido Beltrán, Lluís author Gascón Fora, David author Graciani Díaz, Ricardo author Graugés Pous, Eugeni author Marin Benito, Carla author Picatoste Olloqui, Eduardo author Rives Molina, Vicente José author Ruiz, Hugo (Ruiz Pérez) author Vilasis-Cardona, Xavier author LHCb Collaboration 2019-05-09T09:13:26Z2019-05-09T09:13:26Z2015-09-092019-05-09T09:13:26Z The branching fraction ratio R ( D ∗ ) ≡ B ( ¯ B 0 → D * + τ − ¯ ν τ ) / B ( ¯ B 0 → D * + μ − ¯ ν μ ) is measured using a sample of proton-proton collision data corresponding to 3.0 fb − 1 of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ − → μ − ¯ ν μ ν τ . The semitauonic decay is sensitive to contributions from non-standard-model particles that preferentially couple to the third generation of fermions, in particular, Higgs-like charged scalars. A multidimensional fit to kinematic distributions of the candidate ¯ B 0 decays gives R ( D ∗ ) = 0.336 ± 0.027 ( stat ) ± 0.030 ( syst ) . This result, which is the first measurement of this quantity at a hadron collider, is 2.1 standard deviations larger than the value expected from lepton universality in the standard model. cc by (c) CERN; LHCb Collaboration, 2015 http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Física de partícules Experiments Particle physics Experiments Measurement of the Ratio of Branching Fractions B(¯B0→D*+τ−¯ντ)/B(¯B0→D*+μ−¯νμ) info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion