Probing the impact of Delta-Baryons on Nuclear Matter and Non-Radial Oscillations in Neutron Stars

TL;DR

This study investigates how Delta-baryons influence neutron star properties, especially non-radial oscillation frequencies, using a relativistic mean field approach, and finds significant effects consistent with observational data.

Contribution

It provides new insights into the role of Delta-baryons and meson-baryon couplings on neutron star characteristics within the density-dependent relativistic mean field framework.

Findings

Delta-baryons increase non-radial f-mode frequencies by up to 20%.

Meson-baryon coupling strengths significantly influence neutron star properties.

Results align well with observational data from NICER and LIGO-VIRGO.

Abstract

The presence of heavy baryons, such as $\Delta$-baryons and hyperons can significantly impact various properties of Neutron Stars (NSs), like oscillation frequencies, dimensionless tidal deformability, mass, and radii. We explored these effects within the Density-Dependent Relativistic Mean Field formalism. Our analysis considered $\Delta$-admixed NS matter in both hypernuclear and hyperon-free scenarios, providing insights into particle compositions and their effects on NS properties. Our study of non-radial $f$-mode oscillations revealed a distinct increase in frequency due to the additional baryons. The degree of increase was significantly influenced by the meson-baryon coupling strengths. Notably, the coupling between $\Delta$-resonances and $\sigma$-mesons played a highly influential role. In some cases, it led to an approximately 20\% increase in the $f$-mode oscillation frequency of canonical NSs. These couplings also affect other bulk properties of NSs, including mass, radii, and dimensionless tidal deformability ($\Lambda$). Comparing our results with available observational data from pulsars (NICER) and gravitational waves (LIGO-VIRGO collaboration), we found strong agreement, particularly concerning $\Lambda$.