New Neutron Star Equation of State with Quark-Hadron Crossover

Gordon Baym, Shun Furusawa, Tetsuo Hatsuda, Toru Kojo, Hajime Togashi

Published 2019-03-21Version 1

We introduce an improved version of the zero temperature quark-hadron crossover equation of state, QHC19, which describes hadronic matter by the Togashi et al.~equation of state, and quark matter via the Nambu--Jona-Lasinio model with two phenomenological parameters, a short range universal repulsion between quarks, and an attractive diquark interaction, producing pairing of quarks. We describe the physical ranges of these parameters and find a maximum neutron star mass, 2.35 Msun. After a brief review of the construction of the quark-hadronic equation of state by a constrained interpolation between hadronic and quark regimes of dense matter, we delineate the resultant neutron star properties. These agree very well with the inferences of the LIGO/Virgo collaboration, from GW170817, of the pressure vs. baryon density, neutron star radii, and tidal deformabilities.