Abstract
Possible coexistence of kaon condensation and hyperons in high-density matter in neutron stars are reexamined, by the use of the effective chiral Lagrangian for the kaon-baryon interactions and the nonrelativistic baryon-baryon interaction model. It is shown that a critical density of K^- condensation, obtained based on the usual continuous phase transition, does not always give a correct ground state in the presence of the negatively charged hyperons (Σ^-). We also discuss the equation of state of the kaon-condensed phase in hyperonic matter. We suggest a possible existence of self-bound objects, the whole part of which is composed of high-density matter with kaon condensates.
