Phase diagram of helically imbalanced QCD matter
Abstract
We discuss the influence of a helicity imbalance on the phase diagram of dense QCD at finite temperature. The helical quark number counts the difference between the axial charges carried by quarks and antiquarks. We argue that the helical chemical potential is a thermodynamically relevant quantity in theories with the mass gap generation. Using the linear sigma model coupled to quarks, we show that the presence of the helical density substantially affects the phase diagram of dense quark matter. A moderate helical density makes the chiral phase transition softer while shifting the critical end point towards lower temperatures and higher baryon chemical potentials. As the helical density increases, the segment of the first-order transition disappears, and the chiral transition becomes a soft crossover. At even higher helical chemical potentials, the first-order transition reappears again at the zero-density finite-temperature transition and extends into the interior of the phase diagram. This evolution of the chiral transition reflects the existence of a thermodynamic duality between helical and vector (baryonic) chemical potentials. We also show that the presence of the helicity imbalance of quark matter increases the curvature of the chiral pseudocritical line in QCD.
- Publication:
-
Physical Review D
- Pub Date:
- May 2021
- DOI:
- 10.1103/PhysRevD.103.094015
- arXiv:
- arXiv:2005.03575
- Bibcode:
- 2021PhRvD.103i4015C
- Keywords:
-
- High Energy Physics - Theory;
- High Energy Physics - Phenomenology;
- Nuclear Theory
- E-Print:
- 15 pages, 6 figures