http://arxiv.org/abs/2201.00477
We study a family of equations of state (EoS) for hybrid neutron star (NS) matter. Our hybrid EoS are based on an instantaneous nonlocal version of NJL model in $SU(2)_f$ with vector interactions and color superconductivity describing the quark matter (QM) with a Maxwell construction phase transition to hadronic matter phase described by the “DD2” EoS with excluded volume and a crust at low baryonic densities. The form factor in the QM nonlocal model was fitted to lattice QCD (LQCD) results in the Coulomb gauge. To simultaneously fulfill constraints from NICER and tidal deformability from GW170817 it is necessary to consider a $\mu$ dependent bag constant that mimics confinement. Our results show an asymptotic constant behaviour for the speed of sound that reproduces the conjectured value of $1/3$ from QCD in the free case, and larger constant values in the range 0.4 – 0.6 when interactions are turned on.
G. Contrera, D. Blaschke, J. Carlomagno, et. al.
Tue, 4 Jan 22
2/58
Comments: 17 pages, 7 figures
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