Baryon effects on the location of QCD's critical end point

TL;DR

This study investigates how baryonic effects influence the position of the QCD critical end point using Dyson-Schwinger equations, finding only minor impacts and assessing the robustness of this conclusion.

Contribution

It introduces an estimation of baryonic contributions in Dyson-Schwinger equation calculations of QCD's critical end point, addressing a source of systematic error.

Findings

Baryonic effects have a small influence on the critical end point location.

The robustness of the results was tested by varying chemical potential dependencies.

The study provides insights into systematic uncertainties in QCD phase diagram calculations.

Abstract

The location of the critical end point of QCD has been determined in previous studies of $N_f=2+1$ and $N_f=2+1+1$ dynamical quark flavors using a (truncated) set of Dyson-Schwinger equations for the quark and gluon propagators of Landau-gauge QCD. A source for systematic errors in these calculations has been the omission of terms in the quark-gluon interaction that can be parametrized in terms of baryonic degrees of freedom. These have a potentially large dependence on chemical potential and therefore may affect the location of the critical end point. In this exploratory study we estimate the effects of these contributions, both in the vacuum and at finite temperature and chemical potential. We find only a small influence of baryonic contributions on the location of the critical end point. We estimate the robustness of this result by parameterizing further dependencies on chemical potential.