Dense matter equation of state of a massive neutron star with antikaon condensation

Recent measurements of neutron star mass from several candidates (PSR J1614-2230, PSR J0348+0432, MSP J0740+6620) set the lower bound on the maximum possible mass for this class of compact objects ∼2 M⊙. Existence of stars with high mass brings the possibility of existence of exotic matter (hyperons, meson condensates) at the core region of the objects. In this work, we investigate the (anti)kaon (K-, K̄0) condensation in β-equilibrated nuclear matter within the framework of covariant density functional theory. The functionals in the kaonic sector are constrained by the experimental studies on K- atomic, kaon-nucleon scattering data fits. We find that the equation of state softens with the inclusion of (anti)kaon condensates, which lowers the maximum mass of neutron star. In one of the density-independent coupling cases, the K- condensation is through a first order phase transition type, which produces a 2 M⊙ neutron star. The first order phase transition results in mixed phase region in the inner core of the stars. While K̄0 condensation appears via second-order phase transition for all the models we consider here.