Decoupling of the top-Yukawa coupling in the MSSM

In this talk I show a method to compute the running top-Yukawa coupling in supersymmetric models with heavy mass spectrum based on the *running* and *decoupling* procedure. In order to enable this approach I computed the two-loop SUSY-QCD radiative corrections required in the decoupling process. The method has the advantage that large logarithmic corrections are automatically resummed through the Renormalization Group Equations. As phenomenological application the effects of this approach on the prediction of the lightest Higgs boson mass at three-loop accuracy has been studied. A significant reduction of the renormalization scale dependence as compared to the direct method, that is based on the conversion relation between the running and pole mass for the top quark has been observed. The effect of resummation of large logarithmic contributions consists in an increased prediction for the Higgs boson mass, an observation in agreement with the previous analyses.