Study of pure annihilation type decays $B\to D_s^{\ast }K$

Abstract

In this work, we calculate the rare decays $B^0\to D_s^{\ast -}{K}^{+}$ and $B^{+}\to D_s^{\ast +}{\bar{K}}^0$ in perturbative QCD approach with Sudakov resummation. We give the branching ratio of $10^{-5}$ for $B^0\to D_s^{\ast -}{K}^{+}$, which will be tested soon in $B$ factories. The decay $B^{+}\to D_s^{\ast +}{\bar{K}}^0$ has a very small branching ratio at $\mathcal{O}(10^{-8})$, due to the suppression from CKM matrix elements $|V_{ub}^{\ast }{V}_{cd}|$. It may be sensitive to new physics contributions.

14 pages, 1 figure