The effect of charm quark on the QCD chiral phase diagram

Abstract: We study the influence of charm quark dynamics on the chiral phase structure of Quantum Chromodynamics (QCD) using the recently developed miniDSE scheme of the Dyson-Schwinger equations. By calculating the quark propagator in $2+1$ and $2+1+1$ flavor QCD, we quantify the impact of including the charm quark as a dynamical degree of freedom on the QCD phase diagram. Our results show that the charm quark induces a moderate but noticeable shift to lower chemical potential in the location of the critical endpoint (CEP) by approximately 2-3%. The result in this work indicates that the heavy-flavor dynamics can subtly influence the QCD phase structure and should be taken into account in particular for searching the CEP of QCD.