Tricritical scaling at the N_t=6 chiral phase transition for 2 flavour lattice QCD with staggered quarks

Abstract

We have simulated lattice QCD directly in the chiral limit of zero quark mass by adding an additional, irrelevant 4-fermion interaction to the standard action. Using lattices having temporal extent of six and spatial extents of twelve and eighteen, we find that the theory with 2 massless staggered quark flavors has a second order finite temperature phase transition. The critical exponents ${\beta }_{mag}$, $\delta$ and $\nu$ are measured and favour tricritical behaviour over that expected by universality arguments. The pion screening mass is consistent with zero below the transition, but is degenerate with the nonzero $\sigma (f_0)$ mass above the transition, indicating the restoration of chiral symmetry.

12 pages, 3 postscript figures Letter has been rewritten to reflect a reinterpretation of our results as indicating tricritical critical indices rather than those predicted by standard universality arguments. Some additional analysis which supports this interpretation is included. The comparison of our methods with those of others has been expanded

References in corpus (3)

• A Constituent Quark-Meson Model for Heavy-Meson Processes
• Thermodynamics using Wilson and Staggered Quarks
• Critical Behavior in Nt = 4 Staggered Fermion Thermodynamics

Cited by in corpus (6)

• On the nature of the finite-temperature transition in QCD
• Evidence for O(2) universality at the finite temperature transition for lattice QCD with 2 flavours of massless staggered quarks
• Five-loop epsilon expansion for U(n)xU(m) models: finite-temperature phase transition in light QCD
• Scaling behaviour at the $N_t=6$ chiral phase transition for 2-flavour lattice QCD with massless staggered quarks, and an irrelevant 4-fermion interaction
• Nonlinear Realization of Chiral Symmetry on the Lattice
• Lattice QCD at finite isospin density and/or temperature