Chemical potential response of pseudoscalar meson masses in the Nambu—Jona-Lasinio model

Abstract 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 ( g V =0). Then, we include a non-zero g V and study the effects of g V 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.