微观方法下超核物质中超子软化与核子三体排斥的对比
Hyperonic Softening versus Nucleonic Three-Body Repulsion in Hypernuclear Matter within a microscopic approach
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中文总结 AI 辅助
该研究采用LOCVY方法，通过补充Urbana IX三体核力，探究超核物质中超子软化与核子三体排斥的竞争关系，明确了二者对超核物质能量及饱和性质的影响。
中文摘要 AI 辅助
我们在最低阶约束变分法（LOCV）的超子扩展方法（以下记为LOCVY）框架内，研究由中子、质子和Λ超子构成的冷均匀物质。我们基于两重子相互作用的早期LOCVY计算得到扩展，方法是在Argonne v₁₈核子相互作用基础上补充Urbana IX三体核力，该力在变分框架内被约化为关联权重依赖密度的有效两核子相互作用。NΛ和ΛΛ相互作用保持不变，使当前计算能够分离超子诱导的软化与核子三体排斥之间的竞争关系。我们计算了Λ分数Y_Λ=0、0.1和0.2时，核子组分对称的物质以及无质子的中子-Λ极限下每个重子的能量。含与不含三体力的计算之间的直接差异量化了其依赖密度的贡献，而分解为NN、NΛ和ΛΛ项的补充分析则确定了硬化的微观起源。Urbana IX的贡献随密度增加而愈发具有排斥性，它会抗衡有限Λ含量相关的软化，但通常不会消除该软化。我们还研究了几种给定Λ分数下，含与不含核子三体力时的饱和性质，以阐明奇异数和多体相互作用如何修改饱和点，以及其与经验核物质性质的符合程度。
英文摘要
We investigate cold homogeneous matter composed of neutrons, protons, and $Λ$ hyperons within our hyperonic extension of the lowest-order constrained variational (LOCV) method, hereafter denoted LOCVY. Our earlier LOCVY calculation, based on two-baryon interactions, is extended by supplementing the Argonne $v_{18}$ nucleonic interaction with the Urbana IX three-nucleon force, reduced within the variational framework to a correlation-weighted density-dependent effective two-nucleon interaction. The $NΛ$ and $ΛΛ$ interactions are kept unchanged, allowing the present calculation to isolate the competition between hyperon-induced softening and nucleonic three-body repulsion. The energy per baryon is calculated for fixed $Λ$ fractions $Y_Λ=0$, $0.1$, and $0.2$ in matter with a symmetric nucleonic component and in the proton-free neutron--$Λ$ limit. Direct differences between calculations with and without the three-body force quantify its density-dependent contribution, while a complementary decomposition into $NN$, $NΛ$, and $ΛΛ$ terms identifies the microscopic origin of the stiffening. The Urbana contribution becomes increasingly repulsive with density and opposes, but does not generically remove, the softening associated with a finite $Λ$ content. We further investigate the saturation properties for several prescribed $Λ$ fractions, with and without the nucleonic three-body force, to clarify how strangeness and many-body interactions modify the saturation point and the agreement with empirical nuclear-matter properties.
