2026-04-17T06:10:16Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1312062025-12-05T16:38:33Zcom_2072_1057col_2072_478823col_2072_478904col_2072_478917

RECERCAT author Badalov, Alexey author Calvo Gómez, Míriam author Camboni, Alessandro author Garrido Beltrán, Lluís 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 2019-04-02T11:31:29Z2019-04-02T11:31:29Z2014-07-092019-04-02T11:31:29Z The resonant structure of the reaction ¯ B 0 → J / ψ π + π − is studied using data from 3 fb − 1 of integrated luminosity collected by the LHCb experiment, one third at 7 TeV center-of-mass energy and the remainder at 8 TeV. The invariant mass of the π + π − pair and three decay angular distributions are used to determine the fractions of the resonant and nonresonant components. Six interfering π + π − states, ρ ( 770 ) , f 0 ( 500 ) , f 2 ( 1270 ) , ρ ( 1450 ) , ω ( 782 ) and ρ ( 1700 ) , are required to give a good description of invariant mass spectra and decay angular distributions. The positive and negative charge parity fractions of each of the resonant final states are determined. The f 0 ( 980 ) meson is not seen and the upper limit on its presence, compared with the observed f 0 ( 500 ) rate, is inconsistent with a model where these scalar mesons are formed from two quarks and two antiquarks (tetraquarks) at the eight standard deviation level. In the q ¯ q model, the absolute value of the mixing angle between the f 0 ( 980 ) and the f 0 ( 500 ) scalar mesons is limited to be less than 17° at 90% confidence level. cc by (c) CERN; LHCb Collaboration, 2014 http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Física de partícules Gran Col·lisionador d'Hadrons Ressonància Experiments Particle physics Large Hadron Collider (France and Switzerland) Resonance Experiments Measurement of the resonant and CP components in ¯¯B0 → J/ψπ+π− decays info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion