The decay b→sγ in the MSSM revisited

We present a re-analysis of the decay b→sγ in the Minimal Supersymmetric Standard Model with radiatively induced breaking of the gauge group SU(2)×U(1). We extend this analysis to regions of the supersymmetric parameter space wider than those previously studied. Results are explicitly presented for m_t=150 GeV. We discuss the consequences of a measurement of this decay at the Standard Model level for future searches of charged Higgs and charginos. In spite of the strong sensitivity of this decay to the effects of supersymmetry, we find that, at the moment, no lower limit on the mass of these particles can be obtained. The large chargino contribution to the branching ratio for b→sγ obtained at large values of tan β is effectively reduced by pushing the lightest eigenvalue of the up-squark mass matrix closer to the electroweak scale, i.e. by increasing the degree of degeneracy among the up-squarks.