Modeling Hybrid Stars with an SU(3) non-linear sigma model

TL;DR

This paper models hybrid stars using an SU(3) non-linear sigma model, capturing the transition from hadronic to quark matter and analyzing their structure, rotation effects, and cooling behavior.

Contribution

It introduces an extended SU(3) non-linear sigma model that naturally describes the hadron-quark transition in hybrid stars, including rotation and cooling effects.

Findings

Massive neutron stars with hybrid cores up to 2 km in radius.

Rotating stars have smaller hybrid cores, down to 0.87 km.

Cooling behavior of hybrid stars is analyzed.

Abstract

We study the behavior of hybrid stars using an extended hadronic and quark SU(3) non-linear sigma model. The degrees of freedom change naturally, in this model, from hadrons to quarks as the density/temperature increases. At zero temperature, we reproduce massive neutron stars containing a core of hybrid matter of 2 km for the non-rotating case and 1.18 km and 0.87 km, in the equatorial and polar directions respectively, for stars rotating at the Kepler frequency (physical cases lie in between). The cooling of such stars is also analyzed.