Evidence for the decays B⁰→D¯^(*)0ϕ and updated measurements of the branching fractions of the Bs0→D¯^(*)0ϕ decays

Evidence for the decays B⁰→D¯⁰ϕ and B⁰→D¯^*0ϕ is reported with a significance of 3.6 σ and 4.3 σ, respectively. The analysis employs pp collision data at centre-of-mass energies s = 7, 8 and 13 TeV collected by the LHCb detector and corresponding to an integrated luminosity of 9 fb⁻¹. The branching fractions are measured to be (Formula presented.) In these results, the first uncertainty is statistical, the second systematic, and the third is related to the branching fraction of the B⁰→D¯⁰K⁺K⁻ decay, used for normalisation. By combining the branching fractions of the decays B⁰ → D¯^∗0ϕ and B⁰ → D¯^∗0ω, the ω-ϕ mixing angle δ is constrained to be tan²δ = (3.6 ± 0.7 ± 0.4) × 10⁻³, where the first uncertainty is statistical and the second systematic. An updated measurement of the branching fractions of the B_s⁰ → D¯^∗0ϕ decays, which can be used to determine the CKM angle γ, leads to (Formula presented.) (Figure presented.).