Momentum dependence of the ρ-ω mixing amplitude in a hadronic model

We calculate the momentum dependence of the {ρ}-{ω} mixing amplitude in a purely hadronic model. The basic assumption of the model is that the mixing amplitude is generated by NN{} loops and thus driven entirely by the neutron-proton mass difference. The value of the amplitude at the {ω}-meson point is expressed in terms of only the NN{ω} and NN{ρ} coupling constants. Using values for these couplings constrained by empirical two-nucleon data we obtain a value for the mixing amplitude in agreement with experiment. Extending these results to the spacelike region, we find a {ρ}-{ω} contribution to the NN interaction that is strongly suppressed and opposite in sign relative to the conventional contribution obtained from using the constant on-shell value for the mixing amplitude.