Isospin-invariant Nambu - Jona-Lasinio Model with Complete Set of Spin-1 Excitations

The Nambu-Jona-Lasinio quark model is a successful tool for investigating hadron physics and the spontaneous chiralsymmetry-breaking mechanism. In this paper its generalization for SU(2) isospin group is presented. It includes all possible quantum numbers of spin-1 mesons. Simultaneous consideration of all these states leads to interesting predictions like novel mass formula and relations among meson coupling constants.