Weak radiative decays of Bs mesons.

Abstract

We discuss the main rare radiative decays of the strange ${B}_{s}$ mesons, ${B}_{s}\ensuremath{\rightarrow}\ensuremath{\varphi}\ensuremath{\gamma}$ and ${B}_{s}\ensuremath{\rightarrow}{K}^{*}\ensuremath{\gamma}$. ${B}_{s}\ensuremath{\rightarrow}\ensuremath{\varphi}\ensuremath{\gamma}$ is the dominant mode, expected at a branching ratio of (0.3-0.5)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$. The calculation of these exclusive channels with two different approaches emphasizes an uncertainty in the prediction of about 2-3. Additional modes are ${B}_{s}\ensuremath{\rightarrow}\ensuremath{\varphi}{e}^{+}e$, ${B}_{s}\ensuremath{\rightarrow}\ensuremath{\varphi}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ at the ${10}^{\ensuremath{-}6}$ level and ${B}_{s}\ensuremath{\rightarrow}(\ensuremath{\eta},{\ensuremath{\eta}}^{\ensuremath{'}}){e}^{+}{e}^{\ensuremath{-}}$, ${B}_{s}\ensuremath{\rightarrow}(\ensuremath{\eta},{\ensuremath{\eta}}^{\ensuremath{'}}){\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ at the ${10}^{\ensuremath{-}7}$ level.