Neutron stars with antikaons: Comparison between two ways of extending the relativistic mean field models

Extending the relativistic mean field (RMF) models either with higher order couplings or with density-dependent couplings has been proven to be successful in explaining several properties of finite nuclei, infinite matter, and neutron stars (NSs) in a unified way. Here, we compare how these two extensions fare while explaining NSs with and without antikaons. Both these extensions soften the equation of state (EoS), but the higher order couplings are more efficient in doing so. Even for a very soft EoS, we find that there is a strong possibility of antikaons being condensed. We find an exception for correlation between NS radius and density dependence of symmetry energy, which gets restored when we introduce antikaons. The implication of a precisely measured 2M(circle dot) NS on our results is discussed with four sets of interactions which cover all four combinations of stiff and soft symmetry energy and equations of state. DOI: 10.1103/PhysRevC.87.045802