Observation of $B^0\to D_s^{+}{\pi }^{-}$

Abstract

We report the first observation of $B^0\to D_s^{+}{\pi }^{-}$ and an improved measurement of ${\bar{B}}^0\to D_s^{+}{K}^{-}$ based on $274\times 10^6$ $B\bar{B}$ events collected with the Belle detector at KEKB. We measure the branching fractions $\mathcal{B}({\bar{B}}^0\to D_s^{+}{K}^{-})=(2.93\pm 0.55\pm 0.79)\times 10^{-5}$ and $\mathcal{B}(B^0\to D_s^{+}{\pi }^{-})=(1.94\pm 0.47\pm 0.52)\times 10^{-5}$.

arXiv comment9 pages, 3 figures, submitted to ICHEP2004, Beijing, China