English

Effects of Phi and $\sigma^{*}$-meson on properties of hyperon stars including $\Delta$ resonance

Nuclear Theory 2025-10-17 v6 High Energy Astrophysical Phenomena

Abstract

In this work, we study the properties of neutron stars using the linear Relativistic Mean-Field (RMF) theory and consider multiple degrees of freedom inside neutron stars, including hyperons and Δ\Delta resonances. We investigate different coupling parameters xσΔx_{\sigma \Delta} between Δ\Delta resonances and nucleons and compare the differences between neutron stars with and without strange mesons σ\sigma^* and ϕ\phi. These effects include particle number distributions, equations of state (EOS), mass-radius relations, and tidal deformabilities. To overcome the "hyperon puzzle," we employ the σcut\sigma-cut scheme to obtain neutron stars with masses up to 2M2M_{\odot}. We find that strange mesons appear at around 3ρ0\rho_0 and reduce the critical density of baryons in the high-density region. With increasing coupling parameter xσΔx_{\sigma \Delta}, the Δ\Delta resonances suppress hyperons, leading to a shift of the critical density towards lower values. The early appearance of Δ\Delta resonances may play a crucial role in the stability of neutron stars. Strange mesons soften the EOS slightly, while Δ\Delta resonances predominantly soften the EOS in the low-density region. By calculating tidal deformabilities and comparing with astronomical observation GW170817, we find that the inclusion of Δ\Delta resonances decreases the radius of neutron stars.

Keywords

Cite

@article{arxiv.2308.00007,
  title  = {Effects of Phi and $\sigma^{*}$-meson on properties of hyperon stars including $\Delta$ resonance},
  author = {Chen Wu and Wenjun Guo},
  journal= {arXiv preprint arXiv:2308.00007},
  year   = {2025}
}

Comments

10 pages, 9 figures