Weakened Constraints from b→sγ on Supersymmetry Flavor Mixing Due to Next-To-Leading-Order Corrections

We examine the process B→X_sγ in minimal supersymmetry (SUSY) with general squark flavor mixings. We include all relevant next-to-leading order (NLO) QCD corrections and dominant NLO SUSY effects from the gluino. We find that gluino-squark corrections to down-type quark masses induce large NLO corrections to the dominant Wilson coefficients whose size is often similar to those at LO, especially at large tan⁡β. For μ>0, destructive interference and suppression by the renormalization group running lead to a “focusing effect” of reducing the size of gluino corrections to the branching ratio, and also of reducing the LO sensitivity to flavor mixings among squarks. Constraints from B(B→X_sγ) on the SUSY-breaking scale can become significantly weakened relative to the minimal flavor violation case, even, at large tan⁡β, for small flavor mixings. The case of μ<0 also becomes allowed.