Comerma Montells, AlbertGarcia Moreno, PaulaGarrido Beltrán, LluísGioventù, AlessandraGironella Gironell, PereGomez Fernandez, SergioGraugés Pous, EugeniLobo Salvia, AniolLópez Huertas, AlbertManera Escalero, RafelMarin Benito, CarlaMauricio Ferre, JoanCalefice, LukasVazquez Gomez, RicardoLHCb Collaboration2025-06-272025-06-2720241126-6708https://hdl.handle.net/2445/221852A search for the fully reconstructed B0 s → µ +µ −γ decay is performed at the LHCb experiment using proton-proton collisions at √ s = 13 TeV corresponding to an integrated luminosity of 5.4 fb−1 . No signifcant signal is found and upper limits on the branching fraction in intervals of the dimuon mass are set B(B 0 s → µ +µ −γ) < 4.2 × 10−8 , m(µ +µ −) ∈ [2mµ, 1.70] GeV/c2 , B(B 0 s → µ +µ −γ) < 7.7 × 10−8 , m(µ +µ −) ∈ [1.70, 2.88] GeV/c2 , B(B 0 s → µ +µ −γ) < 4.2 × 10−8 , m(µ +µ −) ∈ [3.92, mB0 s ] GeV/c2 , at 95% confdence level. Additionally, upper limits are set on the branching fraction in the [2mµ, 1.70] GeV/c2 dimuon mass region excluding the contribution from the intermediate ϕ(1020) meson, and in the region combining all dimuon-mass intervals.27 p.application/pdfengcc-by (c) Aaij, R. et al., 2024http://creativecommons.org/licenses/by/4.0/Model estàndard (Física nuclear)Física de partículesHadronsStandard model (Nuclear physics)Particle physicsHadronsinfo:eu-repo/semantics/article7564712025-06-27info:eu-repo/semantics/openAccess