■ Condensation in Neutron Star Matter with △ Quartet

In the framework of relativistic mean field theory, the condensations of K^- and K^0 in neutron star matter including baryon octet and △ quartet are studied. We find that in this case K^- and K^0 condensations can occur at relative shallow optical potential depth of K^ from -80 MeV to -160 MeV. Both K^- and K^0 condensations favor the appearances of △ resonances. With K^- condensations all the △ quartet can appear well inside the maximum mass stars. The appearances of △ resonances change the composition and distribution of particles at high densities. The populations of △ resonances can enhance K^- condensation. It is found that in the core of massive neutron stars, neutron star matter includes rich particle species, such as antikaons, baryon octet, and △ quartet. In the presence of △ resonances and K^- condensation, the EOS becomes softer and results in smaller maximum mass stars. Furthermore the impact of antikaon condensations, hyperons, and △ resonances on direct Urca process with nucleons is also discussed briefly.