FERMI SEA EFFECTS ON PION AND KAON PROPERTIES IN THE NAMBU-JONA-LASINIO MODEL

摘要

We study modifications of hadronic properties in dense nuclear and neutron matter, in the context of a generalized three-flavor Nambu-Jona-Lasinio model, focussing mainly on Fermi sea effects. In symmetric nuclear matter, we observe the splitting between K+/- and the occurrence of a low-lying K- branch at baryonic densities around 0.4 times normal nuclear matter density rho(0). This branch is not significantly affected by the inclusion of strange matter in the medium while the flavor asymmetry is preserved. A similar pi(+) branch is found in neutron matter at neutron densities around 0.3 rho(0), These low-lying modes are panicle-hole excitations of the Fermi sea and decrease smoothly with density. In any case, the vacuum doss not exhibit signs of instability associated with boson condensation. (C) 1997 Elsevier Science B.V. [References: 32]