Connecting neutron star observations to the high density equation of   state of quasi-particle model
  The observation of $1.97\pm0.04$ solar-mass neutron-like star gives constraint on the equation of state (EOS) of cold, condensed matter. In this paper, the EOS for both pure quark star and hybrid star with a quark core described by quasi-particle model are considered. The parameters of quasi-particle model which affect the mass of both quark star and hybrid star can be constrained by the observation. 
Yan Yan, Jing Cao, Xin-Lian Luo, Wei-Min Sun and Hongshi Zong
astro-ph.HE hep-ph nucl-th