Implications of the fermion vacuum term in the extended SU(3) Quark Meson model on compact stars properties

TL;DR

This paper investigates how including the fermion vacuum term in the SU(3) quark meson model affects the equation of state and compact star properties, revealing significant differences from the mean field approximation.

Contribution

It introduces an extended SU(3) quark meson model incorporating the fermion vacuum term and analyzes its impact on stellar properties and phase transitions.

Findings

Extended model restricts parameter space for tidal deformability and mass constraints.

No first order chiral phase transition or twin star solutions in the extended model.

Differences from mean field approximation in star property predictions.

Abstract

We study the impact of the fermion vacuum term in the SU(3) quark meson model on the equation of state and determine the vacuum parameters for various sigma meson masses. We examine its influence on the equation of state and on the resulting mass radius relations for compact stars. The tidal deformability $\Lambda$ of the stars is studied and compared to the results of the mean field approximation. Parameter sets which fulfill the tidal deformability bounds of GW170817 together with the observed two solar mass limit turn out to be restricted to a quite small parameter range in the mean field approximation. The extended version of the model does not yield solutions fulfilling both constraints. Furthermore, no first order chiral phase transition is found in the extended version of the model, not allowing for the twin star solutions found in the mean field approximation.