Next-to-Leading QCD Corrections to $B \to X_{s} \gamma $ in Supersymmetry

We compute the QCD next-to-leading order matching conditions of the (chromo)-magnetic operators relevant for B\to X_s \gamma in supersymmetric models with minimal flavour violation. The calculation is performed under the assumption that the charginos and one stop are lighter than all other squarks and the gluino. In the parameter region where a light charged Higgs boson is consistent with measurements of BR(B\to X_s \gamma), we find sizeable corrections to the Wilson coefficients. As a consequence, there is a significant reduction of the stop-chargino mass region