QCD phase diagram in chiral imbalance with self-consistent mean field approximation

Abstract

We employ a new self-consistent mean field approximation of NJL model, which introduces a free parameter α (α reflects the weight of different interaction channels), to study the effects of the chiral chemical potential µ 5 on QCD phase structure, especially the location of the QCD critical end point (CEP). We find that, at a high temperature, the critical temperature of QCD phase transition smoothly increases with µ 5 at the beginning, and then decreases rapidly. At low temperature and high baryon density region, the increase of the chiral chemical potential will reduce the critical chemical potential of phase transition. The temperature of the CEP shows a non-monotonic dependence on the chiral chemical potential with a long plateau around the maximum. At µ 5 = 0, we found that the CEP will disappear when the α value is larger than 0.71 and will reappear when the µ 5 increases. This study is important for exploring the QCD phase structure and the location of CEP in chiral imbalanced systems.

A Brief Review of Chiral Chemical Potential and Its Physical Effects

“…The results of lattice simulation show that the chiral chemical potential plays the role of a catalyst of spontaneous chiral symmetry breaking and enhance the chiral condensate of quarks [50][51][52]. This result also appears in the model analyses [52][53][54][55]. Moreover, the critical temperature of deconfinement phase transition increases with chiral chemical potential increasing [50,51].…”

“…The Nambu-Jona-Lasinio (NJL) model analyses on the effects of chiral chemical potential are provided in Refs. [52,54,56,57]. The results of Refs.…”

“…The results of Refs. [54,56] show that the chiral chemical potential can reduce the chemical potential of deconfinement phase transition at low temperature and finite density. In Ref.…”

Chiral transition and the chiral charge density of the hot and dense QCD matter.

“…while for NJL model the results differ by regularization schemes [26][27][28][29][30][31]. This problem is also connected with the determination of the CEP.…”

A Study of the Properties of the QCD Phase Diagram in High-Energy Nuclear Collisions

“…This is the characteristic experimental signature of the critical point we are looking for in the heavy-ion collision experiment. Theoretically, the properties of QCD phase diagram at finite baryon density and the signatures of conserved charge fluctuations near the QCD critical point have been extensively studied by various model calculations, such as Lattice QCD [10,[18][19][20][21][22]98], NJL, PNJL model [99][100][101][102][103][104][105][106], PQM, FRG model [107][108][109], Dyson-Schwinger Equation (DSE) method [110][111][112][113], chiral hydrodynamics [114] and other effective models [94, [115][116][117][118][119]. However, one should keep in mind that the above results are under the assumption of thermal equilibrium with infinite and static medium.…”