Amplitude analysis of the Bs0→K∗0K¯∗0 decays and measurement of the branching fraction of the B0→K∗0K¯∗0 decay

Abstract

The B0→K∗0K¯∗0$$ {B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ and Bs0→K∗0K¯∗0$$ {B}_s^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ decays are studied using proton-proton collision data corresponding to an integrated luminosity of 3 fb−1. An untagged and timeintegrated amplitude analysis of B(s)0 → (K+π−)(K−π+) decays in two-body invariant mass regions of 150 MeV/c2 around the K∗0 mass is performed. A stronger longitudinal polarisation fraction in the B0→K∗0K¯∗0$$ {B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ decay, fL = 0.724 ± 0.051 (stat) ± 0.016 (syst), is observed as compared to fL = 0.240 ± 0.031 (stat) ± 0.025 (syst) in the Bs0→K∗0K¯∗0$$ {B}_s^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ decay. The ratio of branching fractions of the two decays is measured and used to determine ℬB0→K∗0K¯∗0=8.0±0.9stat±0.4syst×10−7$$ \mathrm{\mathcal{B}}\left({B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0}\right)=\left(8.0\pm 0.9\left(\mathrm{stat}\right)\pm 0.4\left(\mathrm{syst}\right)\right)\times {10}^{-7} $$.