出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The extension of the Nambu–Jona-Lasinio Model (NJL) [1] with ’t Hoof determinant [2, 3, 4]
to include eight quark interactions [5] has been proposed as a solution for the vacuum stability
problems which have been shown to afflict this model [6]. While the mesonic spectra, which can
now be built on the spontaneously broken vacuum induced by the ‘t Hooft interaction strength, as
opposed to the commonly considered case driven by the four-quark coupling, remains relatively
unchanged (except for the sigma meson mass, which decreases), the study of temperature effects
[7, 8] (SUf (3) massless case and realistic massive cases) has shown interesting new features:
chiral symmetry restoration can occur through a rapid crossover to the unbroken phase with a
slope and critical temperature (Tc) which are regulated by the OZI violating part of the added
eight quark interactions. As a consequence, Tc can be considerably reduced as compared to the
standard approach, in accordance with recent lattice calculations [9]. A first order transition
behavior is also a possible solution within this approach.
