Phase diagram of chirally imbalanced QCD matter

TL;DR

This paper explores how a chiral chemical potential influences the QCD phase diagram, revealing that it tightens the link between phase transitions, lowers critical temperature, and converts crossovers into first-order transitions, facilitating lattice studies.

Contribution

It introduces a detailed analysis of the QCD phase diagram with chiral imbalance using the linear sigma model, highlighting new effects on phase transition properties.

Findings

Chiral chemical potential tightens the link between deconfinement and chiral transitions.

It lowers the critical temperature of the phase transition.

It converts the crossover into a strong first-order transition.

Abstract

We compute the QCD phase diagram in the plane of the chiral chemical potential and temperature using the linear sigma model coupled to quarks and to the Polyakov loop. The chiral chemical potential accounts for effects of imbalanced chirality due to QCD sphaleron transitions which may emerge in heavy-ion collisions. We found three effects caused by the chiral chemical potential: the imbalanced chirality (i) tightens the link between deconfinement and chiral phase transitions; (ii) lowers the common critical temperature; (iii) strengthens the order of the phase transition by converting the crossover into the strong first order phase transition passing via the second order end-point. Since the fermionic determinant with the chiral chemical potential has no sign problem, the chirally imbalanced QCD matter can be studied in numerical lattice simulations.