Effective Higgs-quark-quark couplings from a heavy SUSY spectrum

In this paper we study the Yukawa Higgs-quark-quark interactions that are generated from radiative corrections of squarks and gluinos, in the Minimal Supersymmetric Standard Model. We compute the corrections to the effective action for Higgs and quark fields that are produced by explicit integration, in the path integral formalism, of all the squarks and gluinos, at the one-loop level and order $\alpha_s$. In addition, we consider the limit of nearly degenerate heavy squarks and gluinos, with masses much larger than the electroweak scale, and derive the effective Lagrangian containing all the relevant new local Higgs-quark-quark interactions. We show that these new interactions do remain non-vanishing, even in the case of infinitely heavy supersymmetric particles and, therefore, we demonstrate explicitly the non-decoupling behavior of squarks and gluinos in Higgs bosons physics. We present the set of new Yukawa couplings and finally derive the corresponding one-loop, order $\alpha_s$, corrections to the Higgs bosons partial decay widths into quarks.