  In this work, a modified two-flavor NJL-type model is utilized, in which the
contact current-current interaction is Fierz-transformed into quark-antiquark
interactions and quark-quark interactions, which are directly related to the
chiral condensate and diquark condensate, respectively. Under mean-field
approximation, the chiral condensate and the diquark condensate are studied on
the same footing. We discuss in detail the competition between the chiral
condensate and the diquark condensate, which are exclusively paired with u and
d quarks, while also investigating the order of the chiral phase transition
through an analysis of the resulting chiral susceptibility.
