Abstract
We analyze the impact of several multi-quark interaction channels on the properties of hybrid stars. Four and eight vector interactions were included in the $SU(3)$ NJL model to describe the quark matter, and all vector like interactions were investigated. The hybrid stars were built starting from an hadronic EoS that satisfy presently accepted nuclear matter properties and considering the quark model constrained by the vacuum properties of several light mesons. The interplay between the 8-quark vector interaction and the 4-quark isovector-vector interaction determine the size of the quark core and its strangeness content. The inclusion of a isovector-vector interaction is essential to obtain large $s$-quark contents and a smaller central speed of sound, although this interaction pushes the onset of quarks to larger densities. It is observed that low mass stars, with a mass below 1.4$M_\odot$, may contain a quark core but with small strangeness content. It is shown that the presently existing mass and tidal deformability constraints from NS observations allow for the existence of hybrid stars with a large strangeness content and large quark cores for binary mass ratios $q=M_2/M_1\gtrsim 0.85$.
Highlights
Multimessenger astrophysics provides deeper insights into neutron stars (NS) physics by combining astrophysical observations of electromagnetic radiation and gravitational waves (GW)
The aim of the present work is to analyze the effect of quark matter on the hybrid stars properties
The χω coupling was seen to stiffen the quark equation of state (EoS), with the onset of quarks occurring at larger densities, giving rise to more massive hybrid stars with smaller quark cores
Summary
Multimessenger astrophysics provides deeper insights into neutron stars (NS) physics by combining astrophysical observations of electromagnetic radiation and gravitational waves (GW). The analysis by the LIGO/Virgo Collaboration of the GW170817 NS merger provided important information about NS physics [5,6], e.g., an upper limit of the tidal deformability of a NS star, constraining the high density EoS. Even though the primary binary component is conclusively a black hole of mass 22.2–24.3 M⊙, the nature of the secondary component with a mass 2.50–2.67 M⊙ remains yet inconclusive [14]. Recent estimates for both the mass and radius of the millisecond-pulsar PSR J0030 þ 0451 were put forward by the Neutron Star Interior
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