Vector meson dominance and ρ-ω mixing

Abstract

The scale of a phenomenologically successful charge-symmetry-violating nucleon-nucleon interaction, that attributed to meson exchange with a {Delta}I=1 {rho}-{omega} transition, is set by the Coleman-Glashow SU(2)-breaking tadpole mechanism. A single tadpole scale has been obtained from symmetry arguments, electromagnetic meson and baryon measured mass splittings, and the observed isospin-violating ({Delta}I=1) decay {omega}{r_arrow}{pi}{sup +}{pi}{sup {minus}}. The hadronic realization of this tadpole mechanism lies in the I=1 a{sub 0} scalar meson. We show that measured hadronic and two-photon widths of the a{sub 0} meson, with the aid of the vector meson dominance model, recover the universal Coleman-Glashow tadpole scale. {copyright} {ital 1998} {ital The American Physical Society}