Phenomenological lattice model of the high-temperature phase transition in quantum chromodynamics

We propose a simple phenomenological lattice model for the high-temperature phase transition in a quark-gluon plasma, in which the elementary dynamical variables are Wilson lines and SU(iV) chiral spins. A mean-field analysis of the model shows a second-order chiral phase transition for N=2 and a first-order phase transition for iV=3. We explore the phase diagrams obtained in the mean-field approximation by varying the several parameters of the model, including a mass term that breaks SU(3)XSU{3), leaving SU(2)XSU(2). Our study admits the possibility that the hightemperature phase transition in QCD is a chiral-symmetry-restoring phase transition and not a "deconfinement" phase transition.