2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/192085Within a broad class of models we show that the amplitude for rho^0-omega mixing must vanish at the transition from timelike to spacelike four momentum. Hence in such models the mixing is either zero everywhere or is necessarily momentum-dependent. This lends support to the conclusions of other studies of rho-omega mixing and calls into question standard assumptions about the role of rho-omega mixing in the theoretical understanding of charge-symmetry breaking in nuclear systems.8 pages. Publication details added to title pageHigh Energy Physics - PhenomenologyNuclear Theorytext