KAON PROPERTIES AT FINITE BARYONIC DENSITY - A NONPERTURBATIVE APPROACH

We investigate the behaviour of kaon properties at finite baryonic den sity (rho(u) = rho(d), rho(s) = 0) in the context of a generalized thr ee-flavour Nambu-Jona-Lasinio model. As predicted by different models, a splitting between the K+ and K- masses is found. The present approa ch reveals a novel feature concerning the K- modes: besides the usual branch, starting at rho = 0, a lower K--like branch appears at rho sim ilar or equal to 1.3 rho(0). The last one is situated below a continuu m band of subthreshold resonances of particle-hole excitations of the Fermi sea and decreases smoothly with density. However, the vacuum doe s not show signs of instability related to kaon condensation.