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/2445/221848The ratio of branching fractions between B0 → J/ψπ0 and B+ → J/ψK∗+ decays is measured with proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1 . The measured value is BB0→J/ψπ0 BB+→J/ψK∗+ = (1.153 ± 0.053 ± 0.048) × 10−2 , where the frst uncertainty is statistical and the second is systematic. The branching fraction for B0 → J/ψπ0 decays is determined using the branching fraction of the normalisation channel, resulting in BB0→J/ψπ0 = (1.670 ± 0.077 ± 0.069 ± 0.095) × 10−5 , where the last uncertainty corresponds to that of the external input. This result is consistent with the current world average value and competitive with the most precise single measurement to date.27 p.application/pdfengcc-by (c) Aaij, R. et al., 2024http://creativecommons.org/licenses/by/4.0/HadronsFísica de partículesModel estàndard (Física nuclear)HadronsParticle physicsStandard model (Nuclear physics)info:eu-repo/semantics/article7564672025-06-27info:eu-repo/semantics/openAccess