MESON PROPERTIES IN AN EXTENDED NONLOCAL NJL MODEL

We consider a non-local version of the NJL model, based on a separable quark-quark interaction. The interaction is extended to include terms that bind vector and axial-vector mesons. The nonlocality means that no further regulator is required. Moreover the model is able to confin e the quarks by generating a quark propagator without poles at real en ergies. Working in the ladder approximation, we calculate amplitudes i n Euclidean space and discuss features of their continuation to Minkow ski energies. Conserved currents are constructed and we demonstrate th eir consistency with various Ward identities. Various meson masses are calculated, along with their strong and electromagnetic decay amplitu des. We also calculate the electromagnetic form factor of the pion, as well as form factors associated with the processes gamma gamma --> p i(0) and omega --> pi(0) gamma. The results are found to lead to a sa tisfactory phenomenology and lend some dynamical support to the idea o f vector-meson dominance. (C) 1998 Elsevier Science B.V.