K̄ Condensation in Neutron Star Matter with Δ Quartet

Abstract

In the framework of relativistic mean field theory, the condensations of K− and K̄0 in neutron star matter including baryon octet and Δ quartet are studied. We find that in this case K− and K̄0 condensations can occur at relative shallow optical potential depth of K̄ from −80 MeV to −160 MeV. Both K− and K̄0 condensations favor the appearances of Δ resonances. With K̄ condensations all the Δ quartet can appear well inside the maximum mass stars. The appearances of Δ resonances change the composition and distribution of particles at high densities. The populations of Δ 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 Δ quartet. In the presence of Δ resonances and K̄ condensation, the EOS becomes softer and results in smaller maximum mass stars. Furthermore the impact of antikaon condensations, hyperons, and Δ resonances on direct Urca process with nucleons is also discussed briefly.