Garcia Moreno, PaulaGarrido Beltrán, LluísGironella Gironell, PereGomez Fernandez, SergioGraugés Pous, EugeniLobo Salvia, AniolLópez Huertas, AlbertManera Escalero, RafelMarin Benito, CarlaMauricio Ferre, JoanAlfonso Albero, AlejandroVazquez Gomez, RicardoLHCb Collaboration2025-06-272025-06-2720241126-6708https://hdl.handle.net/2445/221851Abstract: A search for rare B → Dµ+µ − decays is performed using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1 . No signifcant signals are observed in the non-resonant µ +µ − modes, and upper limits of B B0 → D 0 µ +µ − < 5.1 × 10−8 , B  meson with a c and u quark respectively in proton-proton collisions. Each result is either the frst such measurement or an improvement by three orders of magnitude on an existing limit. Separate upper limits are calculated when the muon pair originates from a J/ψ → µ +µ − decay. The branching fraction of B+ c → D+ s J/ψ multiplied by the fragmentation-fraction ratio is measured to be fc fu · B B + c → D+ s J/ψ = (1.63 ± 0.15 ± 0.13) × 10−5 , where the frst uncertainty is statistical and the second systematic.23 p.application/pdfengcc-by (c) Aaij, R. et al., 2024http://creativecommons.org/licenses/by/4.0/Física de partículesModel estàndard (Física nuclear)HadronsParticle physicsStandard model (Nuclear physics)Hadronsinfo:eu-repo/semantics/article7564702025-06-27info:eu-repo/semantics/openAccess