Observation of the $B_s^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0{K}^{\pm }\ddot{I}{€}^{\mp }$ decay

Abstract

Decays of the form $B_{(s)}^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0{h}^{+}{h}^{\left(\prime \right)-}$ ($h^{(\prime )}=K,\ddot{I}€$) are searched for in proton-proton collision data corresponding to an integrated luminosity of $1.0{\mathrm{fb}}^{-1}$ recorded with the LHCb detector. The first observation of the $B_s^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0{K}^{\pm }\ddot{I}{€}^{\mp }$ decay is reported, with significance in excess of 10 standard deviations. The $B^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0{K}^{+}{K}^{-}$ decay is also observed for the first time. The branching fraction of $B^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ is determined, to significantly better precision than previous measurements, using $B^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0$ as a normalisation channel. Branching fractions and upper limits of the other $B_{(s)}^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0{h}^{+}{h}^{\left(\prime \right)-}$ modes are determined relative to that of the $B^0\to J/\ddot{I}ˆK_{\mathrm{S}}^0\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ decay.

24 pages, 12 figures; v2 as published