With a modified chemical potential dependent effective model for the gluon
propagator, we try to locate the critical end point (CEP) of strongly
interacting matter in the framework of Dyson-Schwinger equations (DSE). Beyond
the chiral limit, we find that Nambu solution and Wigner solution could coexist
in some area. Using the CornwallJackiw-Tomboulis (CJT) effective action, we
show that these two phases are connected by a first order phase transition. We
then locate CEP as the end point of the first order phase transition line.
Meanwhile, based on CJT effective action, we give a direct calculation for the
chiral susceptibility and thereby study the crossover.Comment: 9 pages, 7 figures; Version published in JHE