发表机构
Central China Normal University（华中师范大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在相对论平均场框架下，系统探究了对称能不确定性、非线性$\sigma$-$\delta$耦合及暗物质对中子星性质的影响，发现特定耦合和暗物质参数可软化状态方程并满足GW170817约束，且表面曲率与对称能硬度相关。
AI 中文摘要
核对称能密度依赖性的约束不足给致密核物质的状态方程（EOS）以及中子星性质带来了显著的不确定性。我们在相对论平均场（RMF）框架内系统研究了饱和密度 $n_0$ 处对称能 $E_{\rm sym}$ 及其斜率 $L$ 的不确定性如何影响中子星性质，包括非线性 $\sigma$-$\delta$ 耦合和可能的暗物质（DM）混合效应。对于固定的 $E_{\rm sym}(n_0)$ 和 $L(n_0)$，我们发现耦合常数 $g_{\sigma\delta}=-0.004$ 的 $\sigma$-$\delta$ 耦合会导致EOS出现异常软化，同时增加最大中子星质量并减小恒星半径和潮汐形变率。在 $E_{\rm sym}(n_0)=36~\mathrm{MeV}$ 且费米动量 $k_F^{\rm DM}=50~\mathrm{MeV}$ 的暗物质存在时，也观察到类似行为。在这种情况下，RMF EOS满足GW170817的潮汐形变率约束。我们进一步发现，中子星表面曲率与 $E_{\rm sym}$ 的硬度密切相关，较软的对称能对应较大的表面曲率。我们的结果还表明，$E_{\rm sym}$ 在 $n_0$ 附近的行为主要由同位旋标量参数而非同位旋矢量参数主导。
英文摘要
The poorly constrained density dependence of the nuclear symmetry energy introduces significant uncertainties in the equation of state (EOS) of dense nuclear matter and, consequently, in neutron-star properties. We systematically investigate how uncertainties in the symmetry energy $E_{\rm sym}$ and its slope $L$ at saturation density $n_0$ affect NS properties within the relativistic mean-field (RMF) framework, including the effects of nonlinear $σ$-$δ$ coupling and possible admixture of dark matter(DM) . For fixed $E_{\rm sym}(n_0)$ and $L(n_0)$, we find that the $σ$-$δ$ coupling with $g_{σδ}=-0.004$ induces an abnormal softening of the EOS, which simultaneously increasing the maximum NS mass and reducing the stellar radius and tidal deformability. A similar behavior is found in the presence of DM with Fermi momentum $k_F^{\rm DM}=50~\mathrm{MeV}$ at $E_{\rm sym}(n_0)=36~\mathrm{MeV}$. In this case, the RMF EOS satisfies the tidal-deformability constraint from GW170817. We further find that the surface curvature of NSs is strongly correlated with the stiffness of $E_{\rm sym}$, with softer symmetry energy corresponding to larger surface curvature. Our results also indicate that the behavior of $E_{\rm sym}$ around $n_0$ is mainly governed by isoscalar rather than isovector parameters.
