ar X iv : h ep - l at / 0 11 00 89 v 2 3 1 O ct 2 00 1 1 Chemical potential response of pseudoscalar meson masses in the

Using the Nambu–Jona-Lasinio (NJL) model we study chemical potential response of the pion and kaon masses as a function of temperature and chemical potential, i.e., ∂m ∂µ (T , µ). First, we obtain the responses assuming the vector–axial vector coupling is zero (gV =0). Then, we include a non-zero gV and study the effects of gV on the responses. We find that the behavior of ∂m ∂µ for the pion is quite different from that for the kaon. It means that ∂m ∂µ is much dependent on the mass difference between the two quarks, i.e., the u and s quarks (or even between the u and d quarks). Our results may give a clue to future studies of ∂m ∂µ on the lattice.