Possible huge enhancement in the radiative decay of the weal W boson into the charmed DsD_{s} meson

We point out that the rare decay mode $W^{\pm} \rightarrow \gamma + D^{\pm}_{s}$ could be spectacularly enhanced, with a branching ratio around $10^{-6}$ which is three order of magnitude larger than previous predictions. Its observation will determine the W boson mass with great accuracy, providing additional high precision tests of the standard model, as well as reveal eventual deviation from the trilinear non-abelian gauge coupling.Comment: 14, PAR/LPTHE 93 - 0

Study of pure annihilation type decays B→Ds∗KB \to D_s^{*} K

In this work, we calculate the rare decays $B^0 \to D_s^{*-} K^+$ and $B^+ \to D_s^{*+} \bar{K}^0$ in perturbative QCD approach with Sudakov resummation. We give the branching ratio of $10^{-5}$ for $B^0 \to D_s^{*-}K^+$, which will be tested soon in $B$ factories. The decay $B^+ \to D_s^{*+} \bar{K}^0$ has a very small branching ratio at ${\cal O}(10^{-8})$, due to the suppression from CKM matrix elements $|V_{ub}^* V_{cd}|$. It may be sensitive to new physics contributions.Comment: 14 pages, 1 figur