Ruiz, Hugo (Ruiz Pérez)Graciani Díaz, RicardoGarrido Beltrán, LluísGraugés Pous, EugeniLHCb Collaboration2023-03-202023-03-2020110370-2693https://hdl.handle.net/2445/195591Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays B0 s → D+ s Xμ−ν and B0 s → D0 K + Xμ−ν are detected. Two struc- tures are observed in the D0 K + mass spectrum at masses consistent with the known D s1(2536)+ and D∗ s2(2573)+ mesons. The measured branching fractions relative to the total B0 s semileptonic rate are B(B0 s → D∗+ s2 Xμ−ν)/B(B0 s → Xμ−ν) = (3.3 ± 1.0 ± 0.4)%, and B(B0 s → D+ s1 Xμ−ν)/B(B0 s → Xμ−ν) = (5.4 ± 1.2 ± 0.5)%, where the first uncertainty is statistical and the second is systematic. This is the first observation of the D∗+ s2 state in B0 s decays; we also measure its mass and width7 p.application/pdfengcc by-nc-nd (c) CERN, 2011http://creativecommons.org/licenses/by-nc-nd/3.0/es/Física de partículesExperimentsGran Col·lisionador d'HadronsMesons (Física nuclear)Particle physicsExperimentsLarge Hadron Collider (France and Switzerland)Mesons (Nuclear physics)info:eu-repo/semantics/article5961362023-03-20info:eu-repo/semantics/openAccess