The QCD Phase Diagram for Three Degenerate Flavors and Small Baryon Density

TL;DR

This paper maps the QCD phase diagram for three degenerate flavors at small baryon density using imaginary chemical potential simulations, identifying the critical line and endpoint with high precision.

Contribution

It introduces a novel approach combining imaginary chemical potential simulations with Taylor series continuation to accurately determine the critical line and endpoint in the QCD phase diagram.

Findings

Critical line T_c(_B) mapped with high accuracy up to (_B/T)^6

First results on the quark mass dependence of the critical endpoint

Significant differences found compared to other methods' endpoint determinations

Abstract

We present results for the phase diagram of three flavor QCD for \mu_B ~ 500 MeV. Our simulations are performed with imaginary chemical potential \mu_I for which the fermion determinant is positive. Physical observables are then fitted by truncated Taylor series and continued to real chemical potential. We map out the location of the critical line T_c(\mu_B) with an accuracy up to terms of order (\mu_B/T)^6. We also give first results on a determination of the critical endpoint of the transition and its quark mass dependence. Our results for the endpoint differ significantly from those obtained by other methods, and we discuss possible reasons for this.