Gluino Contribution to Radiative B Decays: New Operators, Organization of QCD Corrections and Leading Order Results

The gluino-induced contribution to the decay $b \to s \gamma$ is investigated in supersymmetric frameworks with generic sources of flavour violation. It is emphasized that the operator basis of the standard model effective Hamiltonian is enlarged and that a suitable redefinition allows to realize the usual scheme of leading and next-to-leading logarithmic contributions when QCD corrections are included. The effects of the leading order QCD corrections on the inclusive branching ratio for $b \to s \gamma$ are shown. Constraints on supersymmetric sources of flavour violation are derived.