Measurements of the S-wave fraction in $B^{0}\rightarrow K^{+}\pi^{-}\mu^{+}\mu^{-}$ decays and the $B^{0}\rightarrow K^{\ast}(892)^{0}\mu^{+}\mu^{-}$ differential branching fraction
JHEP 1611 (2016) 047
The collaboration

Abstract
A measurement of the differential branching fraction of the decay B$^{0}$ → K$^{∗}$(892)$^{0}$ μ$^{+}$ μ$^{−}$ is presented together with a determination of the S-wave fraction of the K$^{+}$ π$^{−}$ system in the decay B$^{0}$ → K$^{+}$π$^{−}$ μ$^{+}$ μ$^{−}$. The analysis is based on pp-collision data corresponding to an integrated luminosity of 3 fb$^{−1}$ collected with the LHCb experiment. The measurements are made in bins of the invariant mass squared of the dimuon system, q$^{2}$. Precise theoretical predictions for the differential branching fraction of B$^{0}$ → K$^{∗}$(892)$^{0}$ μ$^{+}$ μ$^{−}$ decays are available for the q$^{2}$ region 1.1 < q$^{2}$ < 6.0 GeV$^{2}$ /c$^{4}$. In this q$^{2}$ region, for the K$^{+}$π$^{−}$ invariant mass range 796 < m$_{Kπ}$ < 996 MeV/c$^{2}$, the S-wave fraction of the K$^{+}$π$^{−}$ system in B$^{0}$ → K$^{+}$π$^{−}$ μ$^{+}$ μ$^{−}$ decays is found to be ${F}_{\mathrm{S}}=0.101\pm 0.017\left(\mathrm{stat}\right)\pm 0.009\left(\mathrm{syst}\right),$ and the differential branching fraction of B$^{0}$ → K$^{∗}$(892)$^{0}$ μ$^{+}$ μ$^{−}$ decays is determined to be $\mathrm{d}\mathrm{\mathcal{B}}/\mathrm{d}{q}^2=\left(0.{392}_{-0.019}^{+0.020}\left(\mathrm{stat}\right)\pm 0.010\left(\mathrm{syst}\right)\pm 0.027\left(\mathrm{norm}\right)\right)\times 1{0}^{-7}{c}^4/{\mathrm{GeV}}^2.$