Observation of the decay $B_s^0\to {\overline{D}}^0{K}^{+}{K}^{-}$

Abstract

The first observation of the $B_s^0\to {\overline{D}}^0{K}^{+}{K}^{-}$ decay is reported, together with the most precise branching fraction measurement of the mode $B^0\to {\overline{D}}^0{K}^{+}{K}^{-}$. The results are obtained from an analysis of $pp$ collision data corresponding to an integrated luminosity of $3.0{\text{fb}}^{-1}$. The data were collected with the LHCb detector at centre-of-mass energies of $7$ and $8$ TeV. The branching fraction of the $B^0\to {\overline{D}}^0{K}^{+}{K}^{-}$ decay is measured relative to that of the decay $B^0\to {\overline{D}}^0\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ to be $$\frac{\mathcal{B}(B^0\to {\overline{D}}^0{K}^{+}{K}^{-})}{\mathcal{B}(B^0\to {\overline{D}}^0\ddot{I}{€}^{+}\ddot{I}{€}^{-})}=(6.9\pm 0.4\pm 0.3)\%,$$ where the first uncertainty is statistical and the second is systematic. The measured branching fraction of the $B_s^0\to {\overline{D}}^0{K}^{+}{K}^{-}$ decay mode relative to that of the corresponding $B^0$ decay is $$\frac{\mathcal{B}(B_s^0\to {\overline{D}}^0{K}^{+}{K}^{-})}{\mathcal{B}(B^0\to {\overline{D}}^0{K}^{+}{K}^{-})}=(93.0\pm 8.9\pm 6.9)\%.$$ Using the known branching fraction of $B^0\to {\overline{D}}^0\ddot{I}{€}^{+}\ddot{I}{€}^{-}$, the values of $\mathcal{B}(B^0\to {\overline{D}}^0{K}^{+}{K}^{-})=(6.1\pm 0.4\pm 0.3\pm 0.3)\times 10^{-5}$, and $\mathcal{B}(B_s^0\to {\overline{D}}^0{K}^{+}{K}^{-})=$ $(5.7\pm 0.5\pm 0.4\pm 0.5)\times 10^{-5}$ are obtained, where the third uncertainties arise from the branching fraction of the decay modes $B^0\to {\overline{D}}^0\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ and $B^0\to {\overline{D}}^0{K}^{+}{K}^{-}$, respectively.

All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2018-014.html