Abstract

This study investigates nuclear matter under extreme temperatures and densities, as those encountered in relativistic heavy-ions collisions. Adopting the two-flavor mean-field Nambu–Jona-Lasinio (NJL) and its Polyakov-loop extended PNJL models, the work explores the scenario of QCD phase transition and the competition between chiral symmetry restoration and deconfinement. Model simulations are carried out at different temperatures and chemical potential to investigate the system on the thermodynamic level and also in respect to the phase boundaries. Among the conclusions are a crossover transition at low chemical potential and a first order transition at high densities and deconfinement and chiral transitions could decouple in some ranges of parameter space. Furthermore, a simplified rate-equation model is employed to investigate the centrality dependence of bottomonium suppression in Au+Au collisions at 200GeVNNs = . Our model includes both color-screening-dissociation as well as regeneration effects and is compared with STAR experimental data of ( )Õ 1S ,and ( )Õ 2S . Results show that the model is able to describe nuclear modification factors up to 25% correctness in various centrality bins and the implication of that is that our model has some phenomenological relevance. The work we reported here is meaningful for the development of the theory of QCD phase diagram and of the evolution of quark-gluon plasma in high energy nuclear collisions.

Keywords

Chiral symmetry restoration, deconfinement transition, quark-gluon plasma (QGP), heavy-ion collisions, relativistic heavy-ion collisions