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arXiv · 2308.00007

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

Chen Wu·Wenjun Guo
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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 $\Delta$ resonances. We investigate different coupling parameters $x_{\sigma \Delta}$ between $\Delta$ resonances and nucleons and compare the differences between neutron stars with and without strange mesons $\sigma^*$ and $\phi$. These effects include particle number distributions, equations of state (EOS), mass-radius relations, and tidal deformabilities. To overcome the "hyperon puzzle," we employ the $\sigma-cut$ scheme to obtain neutron stars with masses up to $2M_{\odot}$. We find that strange mesons appear at around 3$\rho_0$ and reduce the critical density of baryons in the high-density region. With increasing coupling parameter $x_{\sigma \Delta}$, the $\Delta$ resonances suppress hyperons, leading to a shift of the critical density towards lower values. The early appearance of $\Delta$ resonances may play a crucial role in the stability of neutron stars. Strange mesons soften the EOS slightly, while $\Delta$ 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 $\Delta$ resonances decreases the radius of neutron stars.

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Chen Wu, Wenjun Guo. 2023-07-29. Effects of Phi and $\sigma^{*}$-meson on properties of hyperon stars including $\Delta$ resonance. https://doi.org/10.1140/epjp/s13360-025-06145-y

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