REGULARIZATION SCHEME DEPENDENCE OF VACUUM OBSERVABLES IN THE NAMBU-JONA-LASINIO MODEL

We consider a bosonized version of the Nambu-Jona-Lasinio model consisting of classical scalar and pseudoscalar fields. Various regularization schemes (sharp covariant and non-covariant, proper-time and Pauli-Villars) are used in order to determine ultraviolet divergent vacuum observables such as the quark condensate 〈-qq〉 and the current quark mass. Both quantities turn out to be very sensitive to the special choice of the scheme applied. Without further modification the proper-time and Pauli-Villars scheme appear to be unable to reproduce simultaneously the commonly used values of the quark condensate and the current quark mass. © 1990 Springer-Verlag.