GAUGE INVARIANCE AND ANOMALOUS GAUGE BOSON COUPLINGS

Abstract

Using the S--matrix pinch technique we obtain to one loop order, gauge independent $γW^-W^+$ and $Z W^-W^+$ vertices in the context of the standard model, with all incoming momenta off--shell. We show that the vertices so constructed satisfy simple QED--like Ward identities. These gauge invariant vertices give rise to expressions for the magnetic dipole and electric quadrupole form factors of the W gauge boson, which, unlike previous treatments, satisfy the crucial properties of infrared finiteness and perturbative unitarity.