# Influence of EOS on compact star made of hidden sector nucleons

## TL;DR

This paper investigates the properties of compact stars composed of hidden sector nucleons, modeling their equation of state using a hidden sector SU(2) chiral sigma model with vector mesons, and analyzes how parameters influence star characteristics.

## Contribution

It introduces an analytical approach to the equation of state for hidden sector nucleon stars using a mean field approximation and explores parameter effects on star mass and radius.

## Key findings

- Derived an analytical EOS depending on two parameters.
- Analyzed the impact of parameters on mass-radius relations.
- Discussed how maximum stable mass varies with model parameters.

## Abstract

We study compact star made of degenerate hidden sector nucleons which will be a candidate for cold dark matter. A hidden sector like QCD is considered, and as the low energy effective theory we take (hidden sector) $ SU(2) $ chiral sigma model including hidden sector vector meson. With the mean field approximation, we find that one can treat the equation of state (EOS) of our model analytically by introducing a variable which depends on the Fermi momentum. The EOS is specified by the two parameters $ C'_{/sigma} $,$ C'_{/omega} $, and we discuss how these parameters affect on the mass-radius relation for compact star as well as on the EOS. The dependence of the maximum stable mass of compact stars on the parameter $ C'_{/sigma} $ will also be discussed.