2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149281We analyze nonabelian massive Higgs-free theories in the causal Epstein-Glaser approach. Recently, there has been renewed interest in these models. In particular we consider the well-known Curci-Ferrari model and the nonabelian Stückelberg models. We explicitly show the reason why the considered models fail to be unitary. In our approach only the asymptotic (linear) BRS-symmetry has to be considered.13 pages, latex, no figures, published version, some misprints corrected and a few comments addedHigh Energy Physics - TheoryHigh Energy Physics - Phenomenologytext