Evidence for the decays B0 → $$ \overline{D} $$(*)0ϕ and updated measurements of the branching fractions of the $$ {B}_s^0 $$ → $$ \overline{D} $$(*)0ϕ decays

Abstract

Evidence for the decays B0→$$ \overline{D} $$ D ¯ 0ϕ and B0→$$ \overline{D} $$ 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 $$ \sqrt{s} $$ 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$$ {\displaystyle \begin{array}{l}\mathcal{B}\left({B}^0\to {\overline{D}}^0\phi \right)=\left(7.7\pm 2.1\pm 0.7\pm 0.7\right)\times {10}^{-7},\\ {}\mathcal{B}\left({B}^0\to {\overline{D}}^{\ast 0}\phi \right)=\left(2.2\pm 0.5\pm 0.2\pm 0.2\right)\times {10}^{-6}.\end{array}} $$ B B 0 → D ¯ 0 ϕ = 7.7 ± 2.1 ± 0.7 ± 0.7 × 10 − 7 , B B 0 → D ¯ ∗ 0 ϕ = 2.2 ± 0.5 ± 0.2 ± 0.2 × 10 − 6 . In these results, the first uncertainty is statistical, the second systematic, and the third is related to the branching fraction of the B0→$$ \overline{D} $$ D ¯ 0K+K− decay, used for normalisation. By combining the branching fractions of the decays B0 → $$ {\overline{D}}^{\left(\ast \right)0}\phi $$ D ¯ ∗ 0 ϕ and B0 → $$ {\overline{D}}^{\left(\ast \right)0}\omega $$ D ¯ ∗ 0 ω , 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 $$ {B}_s^0 $$ B s 0 → $$ {\overline{D}}^{\left(\ast \right)0}\phi $$ D ¯ ∗ 0 ϕ decays, which can be used to determine the CKM angle γ, leads to$$ {\displaystyle \begin{array}{c}\mathcal{B}\left({B}_s^0\to {\overline{D}}^0\phi \right)=\left(2.30\pm 0.10\pm 0.11\pm 0.20\right)\times {10}^{-5},\\ {}\mathcal{B}\left({B}_s^0\to {\overline{D}}^{\ast 0}\phi \right)=\left(3.17\pm 0.16\pm 0.17\pm 0.27\right)\times {10}^{-5}.\end{array}} $$ B B s 0 → D ¯ 0 ϕ = 2.30 ± 0.10 ± 0.11 ± 0.20 × 10 − 5 , B B s 0 → D ¯ ∗ 0 ϕ = 3.17 ± 0.16 ± 0.17 ± 0.27 × 10 − 5 .