NONPERTURBATIVE CONTRIBUTION TO THE FERMION PROPAGATOR AND DYNAMICAL ELECTROWEAK SYMMETRY-BREAKING

We examine the field-theoretical contribution of fermion-antifermion c ondensates arising from a weak-SU(2) doublet of condensing fermions to electroweak vacuum polarization functions. For the custodial-SU(2) ca se of equal condensates and masses, we find that the condensate contri butions to vacuum polarization functions uphold the electroweak signat ure relation m(w) = m(z)cos theta(w), and that these contributions are decoupled entirely from oblique radiative corrections. If only the up per member of the doublet forms a fermion-antifermion condensate, the relation m(w) = m(z)costheta(w) is again upheld in the limit that the mass of the lower member of the doublet is small compared to that of t he upper member. For this case, the upper-member's fermion-antifermion condensate is shown to enter oblique radiative corrections. In the ab sense of an explicit Higgs mechanism, identification of this doublet w ith (t, b) is shown to be excluded by present empirical bounds on S, T , and U parameters. Further phenomenological consequences of fermion-a ntifermion condensate contributions to the W-Z mass matrix are discuss ed, both in the absense and in the presence of an explicit Higgs mecha nism.