Medium effects of magnetic moments of baryons on neutron stars under strong magnetic fields

TL;DR

This paper explores how density-dependent magnetic moments of baryons influence neutron star properties under strong magnetic fields, revealing that enhanced magnetic moments increase proton fractions and stiffen the equation of state.

Contribution

It introduces the effect of medium-dependent baryon magnetic moments on neutron star matter, showing their impact on particle populations and star maximum masses.

Findings

Enhanced baryon magnetic moments increase proton fractions.

Hyperons are suppressed in strong magnetic fields.

The equation of state becomes stiffer with density-dependent magnetic moments.

Abstract

We investigate medium effects due to density-dependent magnetic moments of baryons on neutron stars under strong magnetic fields. If we allow the variation of anomalous magnetic moments (AMMs) of baryons in dense matter under strong magnetic fields, AMMs of nucleons are enhanced to be larger than those of hyperons. The enhancement naturally affects the chemical potentials of baryons to be large and leads to the increase of a proton fraction. Consequently, it causes the suppression of hyperons, resulting in the stiffness of the equation of state. Under the presumed strong magnetic fields, we evaluate relevant particles' population, the equation of state and the maximum masses of neutron stars by including density-dependent AMMs and compare them with those obtained from AMMs in free space.