Quarks and Compact Stars (QCS)
Oct. 20-22, 2014, KIAA at Peking University, Beijing - P. R. China


Invited Talk

Coexistence of kaon condensation and hyperons in hadronic matter and its relevance to quark matter

Takumi Muto

Department of Physics, Chiba Institute of Technology

Abstract: Multi-strangeness phase consisting of kaon condensation and hyperons in hadronic matter ((Y+K) phase), which may be realized in neutron stars, is investigated. On the basis of the relativistic mean-field theory for baryon-baryon interaction, combined with the effective chiral Lagrangian incorporating $\bar K$-baryon and nonlinear $\bar K-\bar K$ interactions, we obtain onset density of kaon condensation realized from the hyperon-mixed matter and the equation of state (EOS) of the (Y+K) phase. It is shown that coexistence of kaon condensation and hyperon-mixed matter is plausible, but it leads to significant softening of the EOS, which should be reconciled with recent neutron-star observations. We introduce the second-order effects including the range terms for both nucleons and hyperons and a pole contribution from the $\Lambda$ (1405), which are important to be consistent with the result of the s-wave $K (\bar K)-N$ scattering lengths, to conceal the effects of the s-wave scalar attraction between kaons and baryons on the energy and the EOS. Connection of the (Y+K) phase to quark matter is also discussed.