Suppression of thermal vorticity as an indicator of QCD critical point

TL;DR

This paper investigates how the QCD critical point affects the spin polarization of hyperons in quark-gluon plasma, revealing a significant reduction and distinctive rapidity dependence that could serve as experimental signatures.

Contribution

It introduces a numerical study of thermal vorticity and hyperon polarization near the QCD critical point using viscous hydrodynamics with an EoS incorporating the CP effects.

Findings

Global polarization decreases near the CP

Rapid change in polarization with rapidity near the CP

Potential experimental signature of the QCD critical point

Abstract

We study the impact of the QCD critical point (CP) on the spin polarization of $\Lambda$-hyperon generated by the thermal vorticity in viscous quark gluon plasma (QGP). The equations of the relativistic causal viscous hydrodynamics have been solved numerically in (3+1) dimensions to evaluate the thermal vorticity. The effects of the CP have been incorporated through the equation of state (EoS) and the scaling behavior of the transport coefficients. A significant reduction in the global polarization has been found as the CP is approached. A drastic change induced by the CP in the rapidity dependence of the spin polarization is observed which can be used as a signature of the CP.