A nonlinear $R_\xi$--gauge for the electroweak theory

Abstract

A Gauge--fixing procedure for the electroweak theory, based in the BRST symmetry and covariance under the electromagnetic group, is proposed. It is found that in order to have a renormalizable theory, four--ghost interactions must be included in the BRST invariant action, since in this class of gauges these couplings are induced at the one--loop level. This type of gauges allows us to remove several unphysical vertices appearing in conventional linear gauges, which greatly simplifies the loop calculations, since the resultant theory satisfies QED--like Ward identities. Explicit expressions for the Lagrangian of the bosonic sector, including the corresponding ghost term, are presented.