MICROSCOPIC FOUNDATIONS OF THE VECTOR-MESON DOMINANCE MODEL AND THE ANALYSIS OF P-OMEGA MIXING

We use a momentum-space analysis of a generalized Nambu-Jona-Lasinio ( NJL) model to provide a microscopic foundation for the vector-meson-do minance model, (In our model the photon interacts with the constituent quarks rather than with the hadrons.) A novel feature of our model is the introduction of q(2)-dependent meson decay constants, g(rho)(q(2) ) and g(omega)(q(2)) as well as q(2)-dependent meson-meson coupling co nstants, such as g(rho pi pi)(q(2)). We discuss the values of g(rho)(q (2)), g(omega)(q(2)), and g(rho pi pi)(q(2)) obtained using our genera lized NJL model, considering different choices for the parameters of t he model. We also provide a quark-hared description of rho-omega mixin g including die effects of direct omega --> pi(+) + pi(-) decay. The d efinition of momentum-dependent meson decay constants allows us to int roduce current correlation functions for the rho and omega mesons into the analysis in an unambiguous manner, when we start with an analysis of hadronic current correlators that are expressed in terms of quark fields. A good fit is obtained for the pion form factor in the region where rho-omega mixing is important.