The effect of inclusion of $\Delta$ resonances in relativistic mean-field model with scaled hadron masses and coupling constants

TL;DR

This paper investigates how including $$ resonances in a relativistic mean-field model affects the equation of state of baryon matter, with implications for neutron star properties, ensuring consistency with experimental data.

Contribution

The study extends a relativistic mean-field model to incorporate $$ isobars alongside hyperons, analyzing their impact on the equation of state and neutron star constraints.

Findings

Inclusion of $$ resonances softens the equation of state.

The extended model aligns with most experimental constraints.

The model predicts neutron star maximum masses consistent with observations.

Abstract

Knowledge of the equation of state of the baryon matter plays a decisive role in the description of neutron stars. With an increase of the baryon density the filling of Fermi seas of hyperons and $\Delta$ isobars becomes possible. Their inclusion into standard relativistic mean-field models results in a strong softening of the equation of state and a lowering of the maximum neutron star mass below the measured values. We extend a relativistic mean-field model with scaled hadron masses and coupling constants developed in our previous works and take into account now not only hyperons but also the $\Delta$ isobars. We analyze available empirical information to put constraints on coupling constants of $\Delta$s to mesonic mean fields. We show that the resulting equation of state satisfies majority of presently known experimental constraints.