On the asymptotic O(ααS){\cal O}(\alpha \alpha_S) behavior of the electroweak gauge bosons vacuum polarization functions for arbitrary quark masses

We derive the QCD corrections to the electroweak gauge bosons vacuum polarization functions at high and zero--momentum transfer in the case of arbitrary internal quark masses. We then discuss in this general case (i) the connection between the $O(\alpha \alpha_S)$ calculations of the vector bosons self--energies using dimensional regularization and the one performed via a dispersive approach and (ii) the QCD corrections to the $\rho$ parameter for a heavy quark isodoublet.Comment: 14 pages + 2 figures (not included: available by mail from A. Djouadi), Preprint UdeM-LPN-TH-93-156 and NYU-TH-93/05/0