Measurement of $B^0\to D_s^{-}{K}_S^0\ddot{I}{€}^{+}$ and $B^{+}\to D_s^{-}{K}^{+}{K}^{+}$ branching fractions

Abstract

We report a measurement of the $B^0$ and $B^{+}$ meson decays to the $D_s^{-}{K}_S^0\ddot{I}{€}^{+}$ and $D_s^{-}{K}^{+}{K}^{+}$ final states, respectively, using $657\times 10^{6}B\overline{B}$ pairs collected at the $\hat{I}\yen (4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. Using the $D_s^{-}\to \ddot{I}•\ddot{I}{€}^{-}$, $K^{\ast }(892{)}^0{K}^{-}$ and $K_S^0{K}^{-}$ decay modes for the $D_s$ reconstruction, we measure the following branching fractions: $\mathcal{B}(B^0\to D_s^{-}{K}_S^0\ddot{I}{€}^{+})=[0.47\pm 0.06(\mathrm{stat})\pm 0.05(\mathrm{syst})]\times 10^{-4}$ and $\mathcal{B}(B^{+}\to D_s^{-}{K}^{+}{K}^{+})=[0.93\pm 0.22(\mathrm{stat})\pm 0.10(\mathrm{syst})]\times 10^{-5}$. We find the ratio of the branching fraction of $B^{+}\to D_s^{-}{K}^{+}{K}^{+}$ to that of the analogous Cabibbo favored $B^{+}\to D_s^{-}{K}^{+}\ddot{I}{€}^{+}$ decay to be ${\mathcal{R}}_{\mathcal{B}}=0.054\pm 0.013(\mathrm{stat})\pm 0.006(\mathrm{syst})$, which is consistent with the na\"ıve factorization model. We also observe a deviation from the three-body phase-space model for both studied decays.

13 pages, 4 figures, submitted to PRD