Axial anomaly and the three-flavor Nambu--Jona-Lasinio model with confinement: Constructing the QCD phase diagram

TL;DR

This paper extends the three-flavor Nambu-Jona-Lasinio model to include confinement and axial anomaly effects, constructing the QCD phase diagram and exploring critical points and phase transitions.

Contribution

It introduces a combined model incorporating confinement and axial anomaly effects to analyze the QCD phase structure with new insights.

Findings

Identification of a low temperature critical point.

Evidence of a BEC-BCS crossover.

Insights into the interplay between chiral and diquark condensates.

Abstract

We investigate the phase structure of massless three-flavor QCD by extending the Nambu-Jona- Lasinio model to include the effects of confinement and the axial anomaly. We study the interplay between the chiral and diquark condensates induced by the axial anomaly, as well as their relationship with the Polyakov loop, which parameterizes confinement. By minimizing the thermodynamic potential we construct the QCD phase diagram and investigate the possibility of realizing a recently discovered low temperature critical point and an associated BEC-BCS crossover. We also perform a Ginzburg-Landau expansion of the thermodynamic potential, comparing our results to a prior analysis based purely on symmetry considerations, in order to assess the lowest-order effects of the condensate-confinement couplings.