Chiral phase transition in a covariant non-local NJL model

I. J. GENERAL; D. GOMEZ DUMM; N. N. SCOCCOLA

PHYSICS LETTERS B

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2001 p. 267 - 274

0370-2693

The properties of the chiral phase transition at finite temperature and chemical potential are investigated within a nonlocalcovariant extension of the Nambu–Jona-Lasinio model based on a separable quark–quark interaction. We consider both thesituation in which the Minkowski quark propagator has poles at real energies and the case where only complex poles appear. Inthe literature, the latter has been proposed as a realization of confinement. In both cases, the behaviour of the physical quantitiesas functions of T and µ is found to be quite similar. In particular, for low values of T the chiral transition is always of first orderand, for finite quark masses, at certain “end point” the transition turns into a smooth crossover. In the chiral limit, this “endpoint” becomes a “tricritical” point. Our predictions for the position of these points are similar, although somewhat smaller,than previous estimates. Finally, the relation between the deconfining transition and chiral restoration is also discussed.