Abstract
We observe that the electroweak one loop correction to the quark+gluon toquark+Higgs amplitude at high energy involves both single and quadraticlogarithms of the energy in the SM case but only quadratic logarithms in theMSSM case. We explore the origin of this special SUSY cancellation, both in adiagrammatic way and through the splitting+Parameter Renormalization procedure.We show that it is not an accident but a remarkableand general SUSY property ofthe renormalized Higgs-fermion-fermion and Higgsino-sfermion-fermion verticeswhich directly reflects in such processes, for example in $bg\to tH^-$, $bg\tobH^0$, $bg\to bh^0$, $bg\to bA^0$, and through equivalence in $bg\totW^-_{long}$, $bg\to bZ_{long}$, as well as in $bg\to \tilde{t}\chi^-$,$bg\to\tilde{b}\chi^0$. This simplification of the high energy behaviour (whichonly leaves quadratic logarithms involving pure gauge couplings without anyfree parameter) allows to write simple relations among these various processeswhich constitute genuine tests of the assumed SUSY model.