Pion Loop Contribution to Rho-Omega Mixing and Mass Splitting

Abstract

We study the self-energy amplitudes for the rho-omega meson system produced by an effective field theory model at the quark level characterized by a finite range quark-quark interaction and an isospin breaking bare quark mass difference $m_u - m_d$. Dynamical effects associated with confinement and dressing of quarks and the finite size of the produced $\bar{q}q$ meson modes are treated. Parameters of this approach, previously constrained by soft pion physics, are here supplemented in a minimal way to reproduce $m_ω$ and $g_{ρππ}$. Calculations are carried out up to the one pion loop level and the predictions for rho-omega mixing, mass splitting, the rho width and the symmetry breaking omega-pi-pi coupling constant and form factor are presented. The contribution of the direct $ω\rightarrow ππ$ process relative to the $ω\rightarrow ρ\rightarrow ππ$ process is discussed within this model.