Gluon effects on the equation of state of color superconducting strange stars

TL;DR

This paper investigates how gluon effects influence the equation of state of color superconducting quark matter in strange stars, showing that gluons tend to soften the EoS and affect the maximum mass of such stars.

Contribution

It demonstrates that including gluon effects in the color-flavor-locked phase softens the equation of state, impacting the maximum mass of color superconducting strange stars.

Findings

Gluon effects soften the equation of state of color superconducting quark matter.

The maximum stellar mass decreases when gluon effects are considered.

High repulsive vector interactions are needed for stars made of color superconducting matter.

Abstract

Compact astrophysical objects are a window for the study of strongly interacting nuclear matter given the conditions in their interiors, which are not reproduced in a laboratory environment. Much has been debated about their composition with possibilities ranging from a simple mixture of mostly protons and neutrons to deconfined quark matter. Recent observations on the mass of two pulsars, PSR J1614-2230 and PSR J0348+0432, have posed a great restriction on their composition, since the equation of state must be hard enough to support masses of about at least two solar masses. The onset of quarks tends to soften the equation of state, but it can get substantially stiffer since in the high-dense medium a repulsive vector interaction channel is opened. Nevertheless, we show that once gluon effects are considered, the equation of state of quark matter in the color-flavor-locked phase of color superconductivity becomes softer decreasing the maximum stellar mass that can be reached when not considering their influence. This may indicate that stars made entirely of color superconducting matter can only be favored to describe compact stars if the repulsive vector constant is high enough.