We report a measurement of the exclusive $B^{+}$ meson decay to the $D_s^{(*)-}{K}^{+}{\pi }^{+}$ final state using $657\times {10}^{6}B\overline{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. We use $D_s^{*-}\to D_s^{-}\gamma$ and the $D_s^{-}\to \varphi {\pi }^{-}$, ${\overline{K}}^{*}(892{)}^0{K}^{-}$ and $K_S^0{K}^{-}$ decay modes for $D_s^{(*)}$ reconstruction and measure the following branching fractions: $\mathcal{B}(B^{+}\to D_s^{-}{K}^{+}{\pi }^{+})=({1.71}_{-0.07}^{+0.08}(\mathrm{stat}{)}_{-0.20}^{+0.20}(\mathrm{syst})\pm 0.15({\mathcal{B}}_{\mathrm{int}}))\times {10}^{-4}$ and $\mathcal{B}(B^{+}\to D_s^{*-}{K}^{+}{\pi }^{+})=({1.31}_{-0.12}^{+0.13}(\mathrm{stat}{)}_{-0.25}^{+0.25}(\mathrm{syst})\pm 0.12({\mathcal{B}}_{\mathrm{int}}))\times {10}^{-4}$. The uncertainties are due to statistics, experimental systematic errors, and uncertainties of intermediate branching fractions, respectively.

• Received 30 March 2009

DOI:https://doi.org/10.1103/PhysRevD.80.052005