Model Study of a Quark Star

TL;DR

This study applies a QCD-based equation of state to model quark stars, highlighting the significance of the $P(=0)$ term and comparing results with recent observational data.

Contribution

Introduces a quark star model using a specific QCD EOS with a single adjustable parameter and emphasizes the importance of the $P(=0)$ term in the model.

Findings

The $P(=0)$ term significantly affects quark star properties.

Model results are consistent with recent observational data.

Comparison with other models shows the importance of the chosen EOS.

Abstract

In this paper we apply the equation of state (EOS) of QCD at finite chemical potential and zero temperature proposed in H. S. Zong and W. M. Sun [Int. J. Mod. Phys. {\bf A23}, 3591 (2008)] to the study of properties of quark star. This EOS contains only one adjustable parameter $m_D$ which sets the scale of chiral symmetry breaking (in our calculation we have chosen two values of $m_D$: $m_D=244 MeV$ and $m_D=239 MeV$, which is fitted from the value of $f_\pi$ and determined by $e^+ e^-$ annihilation experiment, respectively). From this EOS a model of quark star is established by applying the Tolman-Oppenheimer-Volkoff equation under two conditions: with the $P(\mu=0)$ term and without the $P(\mu=0)$ term. Our results show clearly that the $P(\mu=0)$ term is an important quantity in the study of quark star. A comparison between our model and other models of quark star is made. In particular, we have compared our results with the most recent observational data measured using Shapiro delay reported in P.B. Demorest et al. [Nature (London) {\bf 467}, 1081 (2010)].