Explicit CP Violation in the MSSM Through Higgs --> gamma.gamma

Abstract

The MSSM with explicit CP violation is studied through the di-photon decay channel of the lightest neutral Higgs boson. Through the leading one-loop order H1 --> gammar.gamma is affected by a large number of Higgs-sparticle couplings, which could be complex. Our preliminary scan over the Supersymmetric parameter space shows that more than 50% average deviations are possible, in either direction, in the corresponding branching ratio, with respect to the case of the CP-conserving MSSM. In particular, our analysis shows that in the presence of a light stop (with mass ~ 200 GeV) a CP-violating phase Arg(mu) ~ 90(deg) can render the H1 --> gamma.gamma branching ratio more than 10 times larger, for suitable combinations of the other MSSM parameters.