QCD corrections to the decay H+ → tb in the minimal supersymmetric standard model

We present a complete calculation of the O(αs) QCD corrections to the width of the decay H+ → tb within the Minimal Supersymmetric Standard Model. We find that the QCD corrections are quite important, and that the supersymmetric QCD corrections (due to gluino, t and b exchange) can be comparable to or even larger than the standard QCD corrections in a large region of the supersymmetric parameter space. This is mainly due to the effect of large left-right mixings of stop (t) and sbottom (b). This could significantly affect the phenomennology of the H+ search.