Rho-omega mixing and the pion electromagnetic form-factor

The suggestion of momentum dependence in the amplitude for rho-omega mixing has generated concern over related implications for vector meson dominance and the photon-rho coupling. We discuss two established and formally equivalent representations of vector meson dominance and show that in one of these such a coupling is an automatic consequence of the model. We then apply it to a calculation of the pion electromagnetic form-factor. Our analysis leads to a revised value for the on-shell rho-omega mixing amplitude of −3800 ± 370 MeV2.