Effects of symmetry energy on the direct URCA process in the kaon condensed phase

Abstract
It is investigated whether or not the direct URCA process proceeds in neutron-star matter with kaon condensation, in connection with potential contribution of the nuclear symmetry energy. We find a region in density-symmetry-energy plane in a model-independent way, where the direct URCA process occurs as a unique rapid cooling process in the kaon condensed phase. Symmetry energies with moderate density dependence pass through this region.