The QCD phase diagram at nonzero quark density

TL;DR

This study maps the QCD phase diagram at small to moderate quark densities using lattice simulations, identifying transition lines through chiral condensate and strange quark susceptibility, and finds consistent transition curvature across different lattice spacings.

Contribution

It provides a continuum-extrapolated analysis of the QCD phase transition lines at nonzero chemical potential using improved lattice actions.

Findings

Transition lines have similar curvature after continuum extrapolation.

The width of the transition region remains stable with increasing chemical potential.

Results suggest a consistent phase transition behavior at small to moderate densities.

Abstract

We determine the phase diagram of QCD on the \mu-T plane for small to moderate chemical potentials. Two transition lines are defined with two quantities, the chiral condensate and the strange quark number susceptibility. The calculations are carried out on N_t =6,8 and 10 lattices generated with a Symanzik improved gauge and stout-link improved 2+1 flavor staggered fermion action using physical quark masses. After carrying out the continuum extrapolation we find that both quantities result in a similar curvature of the transition line. Furthermore, our results indicate that in leading order the width of the transition region remains essentially the same as the chemical potential is increased.