On the QCD corrections to $b \to s \gamma$ in supersymmetric models

We reinvestigate the leading QCD corrections to the radiative decay $b \to s \gamma for supersymmetric extensions of the Standard Model. Although the major contributions to the corrections originate from the running of the effective Lagrangian from the W scale down to the$b$ scale, additional corrections are expected from large mass splittings between the particles running in the loops, as well as from integrating out heavy particles at scales different from the W mass. The calculation is performed in the framework of effective field theories.