The QCD critical end point in the PNJL model

¹  Departamento de Física, Universidade de Coimbra - P-3004-516 Coimbra, Portugal, EU
²  E.S.T.G., Instituto Politécnico de Leiria - Morro do Lena-Alto do Vieiro, 2411-901 Leiria, Portugal, EU
³  Université Lyon/UCBL, CNRS/IN2P3, IPNL - 4 rue E. Fermi, F-69622 Villeurbanne Cedex, France, EU

Corresponding author: pcosta@teor.fis.uc.pt

Received: 14 October 2008
Accepted: 14 April 2009

Abstract

We investigate the role played by the Polyakov loop in the dynamics of the chiral phase transition in the framework of the so-called Polyakov-Nambu-Jona-Lasinio (PNJL) model in the SU(2) sector. We present the phase diagram where the inclusion of the Polyakov loop moves the critical points to higher temperatures, compared with the Nambu-Jona-Lasinio model results. The critical properties of physical observables, such as the baryon number susceptibility and the specific heat, are analyzed in the vicinity of the critical end point, with special focus on their critical exponents. The results with the PNJL model are closer to lattice results and we also recover the universal behavior of the critical exponents of both the baryon susceptibility and the specific heat.