Kaon condensation and hyperon mixture in inhomogeneous neutron star matter

Maruyama, Toshiki  ; Muto, Takumi*; Tatsumi, Toshitaka*

It is well-known that mixture of hyperons and kaons in nuclear matter cause softening of matter due to a strong attraction or increased number of degree of freedom. This softening is one of the most serious problems in nuclear physics since one has to sustain an observed heavy neutron star with twice the solar mass. On the other hand, we have investigated the competition of kaon and hyperon mixture in nuclei. Then we found that all the kaons put in nuclei are absorbed in nucleons and converted into hyperons. In the case of nuclear matter in the core of neutron stars, where baryon chemical potential gets high due to the compression of matter, different aspects are observed: hyperons (mainly ) are mixed to reduce baryon chemical potential. With the appearance of kaons, however, repulsion between kaons and hyperons makes the hyperon fraction to decrease. If we take account of inhomogeneous matter, we found that kaons and hyperons distribute separately.