2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149409The concept of perturbative gauge invariance formulated exclusively by means of asymptotic fields is generalized to massive gauge fields. Applying it to the electroweak theory leads to a complete fixing of couplings of scalar and ghost fields and of the coupling to leptons, in agreement with the standard theory. The W/Z mass ratio is also determined, as well as the chiral character of the fermions. We start directly with massive gauge fields and leptons and, nevertheless, obtain a theory which satisfies perturbative gauge invariance.29 pages, latex, no figures, enlarged version. to appear in Ann. Phys. (Leipzig)High Energy Physics - Theorytext