Observation of the $\hat{I}{›}_b^0\to J/\ddot{I}ˆp\ddot{I}{€}^{-}$ decay

Abstract

The first observation of the Cabibbo-suppressed decay $\hat{I}{›}_b^0\to J/\ddot{I}ˆp\ddot{I}{€}^{-}$ is reported using a data sample of proton-proton collisions at 7 and 8 TeV, corresponding to an integrated luminosity of 3 $\mathrm{f}{\mathrm{b}}^{-1}$. A prominent signal is observed and the branching fraction relative to the decay mode $\hat{I}{›}_b^0\to J/\ddot{I}ˆp{K}^{-}$ is determined to be $$\frac{\mathcal{B}(\hat{I}{›}_b^0\to J/\ddot{I}ˆp\ddot{I}{€}^{-})}{\mathcal{B}(\hat{I}{›}_b^0\to J/\ddot{I}ˆp{K}^{-})}=0.0824\pm 0.0025(\text{stat})\pm 0.0042(\text{syst}).$$ A search for direct CP violation is performed. The difference in the CP asymmetries between these two decays is found to be $${\mathcal{A}}_{CP}(\hat{I}{›}_b^0\to J/\ddot{I}ˆp\ddot{I}{€}^{-})-{\mathcal{A}}_{CP}(\hat{I}{›}_b^0\to J/\ddot{I}ˆp{K}^{-})=(+5.7\pm 2.4(\text{stat})\pm 1.2(\text{syst}))\%,$$ which is compatible with CP symmetry at the $2.2\ddot{I}ƒ$ level.