Neutron stars and quark phases in the Nambu–Jona-Lasinio model

We study the possible existence of deconfined quark matter in the interior of neutron stars using the Nambu{endash}Jona-Lasinio model to describe the quark phase. We find that typical neutron stars with masses around 1.4 solar masses do not possess any deconfined quark matter in their center. This can be traced back to the property of the NJL model which suggests a large constituent strange quark mass over a wide range of densities. {copyright} {ital 1999} {ital The American Physical Society}