B_s --> \gamma \gamma decay in the two Higgs doublet model with flavor changing neutral currents

Abstract

We calculate the leading logarithmic QCD corrections to the decay B_{s} -->\gamma\gamma in the two Higgs doublet model with tree level flavor changing currents (model III) including O_7 type long distance effects. Further, we analyse the dependencies of the branching ratio Br(B_{s} --> \gamma\gamma)$ and the ratio of CP-even and CP-odd amplitude squares, R=|A^{+}|^2/|A^{-}|^2, on the charged Higgs mass m_{H^{\pm}} and the selected model III parameters \xi^{U,D} including the leading logarithmic QCD corrections. It is found that to look for charged Higgs effects, the measurement of the branching ratio Br(B_{s} --> \gamma\gamma)$ is promising.