REGULARIZATION IN THE GAUGED NAMBU-JONA-LASINIO MODEL

Various prescriptions employed for regulating gauged Nambu-Jona-Lasini o-type models such as the top-quark condensate model are discussed. Th e use of dimensional regularization maintains gauge invariance but des troys the quadratic divergence in the gap equation. If instead a simpl e ultraviolet momentum cutoff is used to regulate loop integrals, then gauge invariance is destroyed by a quadratically divergent term as we ll as by ambiguities associated with arbitrary routing of loop momenta , Finally it is shown that one can use dispersion relations to regulat e the top-quark condensate model. This prescription maintains gauge in variance and does not depend on arbitrary shifts in loop momenta.