Nonextensive effects on QCD chiral phase transition with a chiral chemical potential

In this study, we investigate the QCD chiral phase diagram in the presence of a chiral chemical potential mu(5) based on nonextensive statistical mechanics. A feature of this new statistic is a dimensionless nonextensivity parameter q, which summarizes all possible effects violating the assumptions of Boltzmann-Gibbs (BG) statistics (when q -> 1, it returns to the BG case). Within the nonextensive Polyakov-Nambu-Jona-Lasinio model, we find that as increases, the critical end point (CEP) in the T - mu plane continues to CEP5 in the T - mu(5) plane, and nonextensive effects have a significant impact on the evolution from the CEP to CEP5. Generally, with an increase in q, both the CEP and CEP5 move in the direction of a lower temperature T and larger chemical potential mu (mu(5)). In addition, we find that chiral charge density generally increases with T, mu, mu(5), and q. Our study may provide useful hints about lattice QCD and relativistic heavy-ion collision experiments.