Green functions from a gauge-invariant effective action for the electroweak Standard Model

Abstract

Application of the background-field method to the electroweak Standard-Model yields a gauge-invariant effective action giving rise to simple Ward identities. We find that in the background-field `t Hooft-Feynman gauge the resulting vertex functions are exactly those that are obtained using the pinch technique. Thus, the background-field method provides a general framework that generalizes the pinch technique directly and uniquely to arbitrary Green functions and arbitrary orders of perturbation theory. Moreover, the desirable properties of the pinch-technique vertex functions hold for arbitrary gauge parameters and have a simple explanation within the background- field method.

to appear in Nucl. Phys. B Proc. Suppl., proceedings to the 1994 Zeuthen workshop on elementary particle theory, "physics at LEP200 and beyond", 6 pages uuencoded postscript, BI-TP 94/22