Leading logarithmic QCD corrections to the Bs → γγ decays in the two-Higgs doublet model

We calculate the leading logarithmic QCD corrections to the decay Bs → γγ in the two-Higgs doublet model (2HDM) including O7-type long-distance effects and estimate the restrictions of the 2HDM parameters, tan β and mH, using the experimental data of B → Xsγ decay provided by the CLEO Collaboration. A lower bound for the charged Higgs mass mH as a function of the renormalization scale μ is given for 2HDM model II. We further present the dependencies of the branching ratio Br(Bs → γγ) and the ratio |A+|2/|A−|2 on mH and tan β logarithmic QCD corrections. The dependence on the renormalization scale is found to be strong for both ratios. An additional uncertainty arises from the variation of the parameters of the bound state model, (mb, Λs). We see that to look for charged Higgs effects the measurement of the branching ratio Br(Bs → γγ) is promising.