THERMODYNAMICS OF LATTICE QCD WITH CHIRAL 4-FERMION INTERACTIONS - ART. NO. 034504

We have studied lattice QCD with an additional, irrelevant l-fermion i nteraction having a U(1) X U(1) chiral symmetry, at finite temperature s. Adding this 4-fermion term allowed us to work at zero quark mass, w hich would have otherwise been impossible. The theory with 2 massless staggered quark flavors appears to have a first order finite temperatu re phase transition at N-t=4 for the value of 4-fermion coupling we ha ve chosen, in contrast to what is expected for 2-flavor QCD. The pion screening mass is seen to vanish below this transition, only to become massive and degenerate with the sigma (f(0)) above this transition wh ere the chiral symmetry is restored, as is seen by the vanishing of th e chiral condensate. [S0556-2821(98)06915-X].