Alternative approach to b → sγ in the uMSSM

Abstract

The gluino contributions to the C′7,8 Wilson coefficients for bsg are calculated within the unconstrained MSSM. New stringent bounds on the δ23RL and δ23RR mass insertion parameters are obtained in the limit in which the SM and SUSY contributions to C7,8 approximately cancel. Such a cancellation can plausibly appear within several classes of SUSY breaking models in which the trilinear couplings exhibit a factorized structure proportional to the Yukawa matrices. Assuming this cancellation takes place, we perform an analysis of the b → sγ decay. We show that, in a supersymmetric world, such an alternative is reasonable and it is possible to saturate the b → sγ branching ratio and produce a CP asymmetry of up to 20%, from only the gluino contribution to C′7,8 coefficients. Using photon polarization a LR asymmetry can be defined that in principle allows the C7,8 and C′7,8 contributions to the b → sγ decay to be disentangled.