Delta Baryons in Neutron-Star Matter under Strong Magnetic Fields

TL;DR

This study investigates how strong magnetic fields influence the composition and structure of neutron star matter, revealing that magnetic fields and meson interactions promote $$Delta baryons and affect star radii.

Contribution

It introduces the effects of magnetic fields and vector-isovector interactions on $$Delta baryon populations in neutron stars using two relativistic models, enhancing understanding of dense matter composition.

Findings

Magnetic fields increase $$Delta baryons in dense matter.

Vector-isovector interactions have minimal impact on neutron star masses.

Magnetic fields decrease neutron star radii, improving model-observation agreement.

Abstract

In this work, we study magnetic field effects on neutron star matter containing the baryon octet and additional heavier spin 3/2 baryons (the $\Delta$'s). We make use of two different relativistic hadronic models that contain an additional vector-isovector self interaction for the mesons: one version of a relativistic mean field (RMF) model and the Chiral Mean Field (CMF) model. We find that both the additional interaction and a strong magnetic field enhance the $\Delta$ baryon population in dense matter, while decreasing the relative density of hyperons. At the same time that the vector-isovector meson interaction modifies neutron-star masses very little ($<0.1~M_\odot$), it decreases their radii considerably, allowing both models to be in better agreement with observations. Together, these features indicate that magnetic neutron stars are likely to contain $\Delta$ baryons in their interior.