发表机构
School of Physics, Southeast University（东南大学物理学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在双流体框架下研究暗物质对中子星压力-半径标度关系的影响，发现暗物质粒子质量、含量和自相互作用会修正该关系，并影响核状态方程的提取。
AI 中文摘要
中子星的半径与不对称核物质的状态方程（EOS）密切相关，尤其是与核对称能有关。在恒星质量固定时，中子星半径与接近饱和密度的核物质压力近似满足压力-半径（R-P）标度关系，将恒星几何与强相互作用物质联系起来。在存在暗物质（DM）的情况下，恒星几何的变化可能改变这一关系。我们研究了GeV和亚GeV量级的暗物质如何在仅引力的双流体框架内影响暗物质混合中子星（DANSs）中的R-P关系。我们将Buchdahl解析解扩展到双流体构型以展示这一标度关系，然后使用21种核EOS拟合$R_{\rm NM}=\bar C P_{\rm NM}^{\eta}$关系，针对$1M_\odot$和$1.4M_\odot$的DANSs。指数$\eta$和系数$\bar C$共同量化了暗物质引起的修正，并依赖于暗物质粒子质量、恒星暗物质含量和自相互作用强度。对于玻色子暗物质，$\eta$和$\bar C$的变化主要发生在亚GeV范围内，而显著的费米子暗物质效应持续到约1.5 GeV。增加暗物质含量或增强排斥性自相互作用通常会增加$\eta$并减小$\bar C$。因此，修正后的R-P关系编码了暗物质粒子质量、丰度和自相互作用的信息，并影响从天体观测中提取核EOS。在暗物质质量为几百MeV时，费米子和玻色子暗物质都可能产生暗物质主导的低质量（$1M_\odot$）DANSs，具有较大的径向延伸，此时常规标度关系不再适用。
英文摘要
The radius of a neutron star is closely related to the equation of state (EOS) of asymmetric nuclear matter, particularly to the nuclear symmetry energy. At fixed stellar mass, the neutron-star radius and the nuclear-matter pressure near saturation density approximately satisfy a pressure--radius (R-P) scaling relation, linking stellar geometry to strong-interaction matter. In the presence of dark matter (DM), changes in the stellar geometry can modify this relation. We investigate how GeV- and sub-GeV-scale DM affects the R-P relation in DM-admixed neutron stars (DANSs) within a gravity-only two-fluid framework. We extend the Buchdahl analytic solution to a two-fluid configuration to demonstrate this scaling and then use 21 nuclear EOSs to fit the relation $R_{\rm NM}=\bar C P_{\rm NM}^η$ for $1M_\odot$ and $1.4M_\odot$ DANSs. The exponent $η$ and coefficient $\bar C$ jointly quantify the DM-induced modification and depend on the DM particle mass, stellar DM content, and self-interaction strength. For bosonic DM, changes in $η$ and $\bar C$ occur mainly in the sub-GeV range, whereas significant fermionic-DM effects persist up to about 1.5 GeV. Increasing the DM content or strengthening a repulsive self-interaction generally increases $η$ and decreases $\bar C$. The modified R-P relation therefore encodes information about the DM particle mass, abundance, and self-interaction, and affect the extraction of the nuclear EOS from celestial observations. At DM masses of several hundred MeV, both fermionic and bosonic DM can also produce DM-dominated low-mass ($1M_\odot$) DANSs with large radial extensions, for which the conventional scaling relation ceases to apply.
