Strongly Interacting Quark Matter in Massive Quark Stars

Abstract

This paper investigates the properties of strongly coupled matter at high baryon densities (\(\rho_B\)) in quark stars (QSs). The QS model is based on the density-dependent quark mass (DDQM) framework, modified (MDDQM) by enhancing the single-gluon interaction to generate higher repulsive pressure. The model parameters are constrained using Bayesian inference, incorporating observational data from the pulsars HESS J1731$-$347, PSR J0030$+$0451, PSR J0740$+$6620, and PSR J0952$-$0607. Our results show that the MDDQM model produces QSs with higher mass and compactness compared to the DDQM model. Among the four MDDQM parameterizations studied, two yield maximum star masses of 1.86 and 2.10 \(\rm M_\odot\) and exhibit near-conformal behavior in the underlying quark matter (QM). The other two parameterizations, yielding QS masses of 2.30 and 2.37 \(\rm M_\odot\), correspond to a stronger interaction in the underlying QM. These findings provide important insights into the equation of state of deconfined QM and its implications for the structure and stability of QSs.