Regularization dependence on phase diagram in Nambu-Jona-Lasinio model

We study the regularization dependence on meson properties and the phase diagram of quark matter by using the two flavor Nambu-Jona-Lasinio model. We find that the meson properties and the phase structure do not show drastically difference depending the regularization procedures. We also find that the location or the existence of the critical end point highly depends on the regularization methods and the model parameters. Then we think that regularization and parameters are carefully considered when one investigates the QCD critical end point in the effective model studies.

Phase diagram of Nambu-Jona-Lasinio model with dimensional regularization

We investigate the phase diagram on temperature-chemical potential plane in the Nambu-Jona-Lasinio model with the dimensional regularization. While the structure of the resulting diagram shows resemblance to the one in the frequently used cutoff regularization, some results of our study indicate striking difference between these regularizations. The diagram in the dimensional regularization exhibits strong tendency of the first order phase transition.