Impact of the Nuclear Equation of State on the Stability of Hybrid Neutron Stars

TL;DR

This paper explores how different nuclear equations of state, especially those involving phase transitions to quark matter, influence the stability and structure of hybrid neutron stars, affecting their mass-radius relationships.

Contribution

It introduces a novel two-phase model combining relativistic mean field theory and vBag with vector interactions, linking hadronic and quark matter equations of state.

Findings

Hybrid star mass-radius relations are significantly affected by the EoS choice.

The model predicts stable hybrid neutron stars with distinct mass and radius characteristics.

The connection between hadronic and quark phases influences the maximum mass of neutron stars.

Abstract

We construct a set of equations of state (EoS) of dense and hot matter with a 1st order phase transition from a hadronic system to a deconfined quark matter state. In this two-phase approach, hadrons are described using the relativistic mean field theory with different parametrisations and the deconfined quark phase is modeled using vBag, a bag-type model extended to include vector interactions as well as a simultaneous onset of chiral symmetry restoration and deconfinement. This feature results in a non-trivial connection between the hadron and quark EoS, modifying the quark phase beyond its onset density. We find that this unique property has an impact on the predicted hybrid (quark core) neutron star mass--radius relations.