Evaluation of particle--anti-particle scaled correlation within effective models

TL;DR

This paper investigates the quark--anti-quark scaled correlation near the QCD critical point using the Nambu--Jona-Lasinio model, highlighting its potential as an experimental signature and examining the impact of vector interactions.

Contribution

It introduces the off-diagonal quark susceptibility as a measure of scaled correlation and analyzes its behavior near the critical point within an effective model.

Findings

Correlation peaks near the critical point, indicating experimental detectability.

Repulsive vector coupling diminishes the correlation strength.

The scaled correlation could serve as a signature for the QCD critical point.

Abstract

Correlations and fluctuations of physical quantities are known to play an important role in phase transitions and critical phenomena. In recent years some experimental attempts were made in the scope of the Beam Energy Scan program to locate a possible critical point in the QCD phase diagram. In this work we use the Nambu--Jona-Lasinio model to investigate the off-diagonal quark susceptibility, which is related to the quark--anti-quark scaled correlation at the mean field level. We show that this correlation has a significant peak near the critical point and, therefore, may be a useful quantity to measure in experiment. We further study the effects of a repulsive vector coupling, which reduces the strength of the scaled correlation near the critical point.