Maximum Mass of Hybrid Stars in the Quark Bag Model

TL;DR

This paper investigates how the parameters in the quark matter equation of state affect the maximum mass of hybrid stars, showing that certain parameter ranges can produce stars matching the mass of the most massive observed pulsars.

Contribution

It provides a detailed analysis of the influence of the bag constant and strong interaction constant on hybrid star maximum mass using the extended MIT bag model and relativistic nucleon matter equations.

Findings

Maximum mass increases as the bag constant decreases.

Maximum mass increases with higher strong interaction constant $\alpha_s$.

Hybrid stars with masses exceeding the most massive pulsars are possible for $\alpha_s > 0.6$ and low bag constants.

Abstract

The effect of model parameters in the equation of state for quark matter on the magnitude of the maximum mass of hybrid stars is examined. Quark matter is described in terms of the extended MIT bag model including corrections for one-gluon exchange. For nucleon matter in the range of densities corresponding to the phase transition, a relativistic equation of state is used that is calculated with two particle correlations taken into account based on using the Bonn meson-exchange potential. The Maxwell construction is used to calculate the characteristics of the first order phase transition and it is shown that for a fixed value of the strong interaction constant $\alpha_s$, the baryon concentrations of the coexisting phases grow monotonically as the bag constant B increases. It is shown that for a fixed value of the strong interaction constant $\alpha_s$, the maximum mass of a hybrid star increases as the bag constant $B$ decreases. For a given value of the bag parameter $B$, the maximum mass rises as the strong interaction constant $\alpha_s$ increases. It is shown that the configurations of hybrid stars with maximum masses equal to or exceeding the mass of the currently known most massive pulsar are possible for values of the strong interaction constant $\alpha_s>0.6$ and sufficiently low values of the bag constant.