Drag force near the QCD critical point

TL;DR

This paper investigates how heavy quark motion is influenced by critical fluctuations near the QCD critical point, revealing different scaling behaviors in various dynamic models and their implications for quark diffusion.

Contribution

It introduces a scaling relation for the heavy quark momentum diffusion constant near the QCD critical point, highlighting differences between model H and B scenarios.

Findings

In model H, the diffusion constant shows weak critical singularity.

In model B, the diffusion constant diverges as the critical point is approached.

The critical dynamics significantly affect heavy quark transport properties.

Abstract

We discuss how heavy quark dynamics is affected by the critical fluctuations near the QCD critical point at finite temperature and density. We find that the heavy quark momentum diffusion constant scales as $\kappa\propto\xi^{z-3-\eta}$. In the model H scenario, which is widely accepted for the critical dynamics, the exponents are known as $z\simeq 3, \eta\sim 0.04$ and the critical singularity of $\kappa$ is not significant if any. In the model B scenario, $z\simeq 4$ and $\kappa\propto \xi$ is singular near the critical point.