Kiro Miyazaki
Stiff equation-of-state of neutron star due to antikaon condensation
(329K, PDF)

ABSTRACT.  We re-examine the antikaon condensation in neutron star (NS) matter within the extended Zimanyi-Moszkowski model. The meson-kaon coupling constants are independent of mean-field and are determined to reproduce kaon potential U_{K}(\rho_{NM})=-120MeV, -140MeV or -170MeV in a saturated nuclear matter. In contrast to all the preceding works, we find that a deeper kaon potential produces a stiffer EOS. This is because the abundance of antikaons tends to exclude s in NS matter and so the strange scalar mean-field becomes weaker. For U_{K}(\rho_{NM})=-120MeV there are no antikaons in NSs, and the massive NSs of M_{G}>1.6M_{\odot} are not reproduced although we have found a branch for the third family of compact stars. The result for U_{K}(\rho_{NM})=-140MeV reproduces the massive NSs but not the mass and radius of EXO 0748-676. Only the result using the very deep kaon potential U_{K}(\rho_{NM})=-170MeV is satisfactory. This is consistent to the recent experimental information on K^- atom and deeply bound kaonic states. Consequently, the antikaon condensed phase is likely to exist in NSs.