Two-solar-mass hybrid stars: a two model description with the   Nambu-Jona-Lasinio quark model
  Hybrid stars with a quark phase described by the Nambu$-$Jona-Lasinio model are studied. The hadron-quark model used to determine the stellar matter equation of state favors the appearance of quark matter: the coincidence of the deconfinement and chiral transitions and a low vacuum constituent quark mass. These two properties are essential to build equations of state that predict pure quark matter in the center of neutron stars. The effect of vector-isoscalar and vector-isovector terms is discussed, and it is shown that the vector-isoscalar terms are necessary to describe 2$M_\odot$ hybrid stars, and the vector-isovector terms result in larger quark cores and a smaller deconfinement density. 
Renan C\^amara Pereira, Pedro Costa, Constan\c{c}a Provid\^encia
nucl-th hep-ph