On the Long Distance Contribution to the $B_s\to \gamma\gamma$ Decay in the Effective Lagrangian Approach

Abstract

We re-estimate the decay branching ratio of $B_s\to 2\gamma$ through $D_s^+D_s^-$ and $D_s^{*+}D_s^{*-}$ intermediate states, in the effective Lagrangian approach. We find that the branching ratio does not exceed a few times $10^{-7}$, contrary to the result recently claimed in the literature.