A theoretical Study of Structure of Superhigh-density Stars based on Realistic Interactions between Baryons

基于现实重子相互作用的超高密度恒星结构理论研究

基本信息

批准号：
15540264
负责人：
SHINMURA Shoji
金额：
$ 0.77万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

In this research, main achievements are summarized in the following three points. [A] We constructed a potential model for realistic baryon-baryon interactions. Using recent data of double hypernuclei, we improved the interaction model and proposed a new potential model referred to as GSOBEP. We determined the properties of few-body double hypernuclei based on the full coupled-channel baryon-baryon (S=-2) interaction (ΛΛ-ΞN-ΣΣ interaction). [B] We developed a computer code to calculate the equation of state (EOS) of high-densitybaryonic matter. This is an extended version of the C-matrix code for ordinary nuclear matter. This code can treat baryonic matter with arbitrary baryon compsitions, and also can determine EOS of β-stable, charge-neutral baryonic matter including leptons, which is believed to be realized in core region of neutron stars. [C] Using the code mentioned above, we determined EOS of high-density baryonic matter with realistic baryon-baryon interactions and found that by the effect of hyperon mixing, EOS become too soft to reproduce the properties (masses and radii) of neutron stars. In addition, we proposed generalized three-baryon force (ππ3BF), which is a generalization of two-pion-exchange Δ-mechanism of three nucleon force (ππ3NF) and apply ππ3BF to neutron-star matter. As a result, ππ3BF is found to provide attractive contribution and soften the EOS further. Then we intreoduced a phenomenological short-range three baryon force (short-3BF), which are extended from short-range three-nucleon force introduced to reproduce the symmetric energy of nuclear matter. We found that short-3BF makes EOS stiff and the EOS is reasonable to reproduce observed masses ans radii of neutron stars.

在这项研究中，主要成就在以下三点中总结了。 [a]我们构建了一个现实的巴属 - 巴里昂相互作用的潜在模型。使用双重颈椎的最新数据，我们改进了相互作用模型，并提出了一个新的潜在模型，称为Gsobep。我们基于完整的耦合通道baryon-baryon（s = -2）相互作用（λλ-ξn-σς相互作用），确定了几型双体双颈椎的属性。 [b]我们开发了计算机代码来计算高密度baryonic物质状态（EOS）的方程。这是用于普通核物质的C-Matrix代码的扩展版本。该代码可以用任意的重子组成处理重型物质，还可以确定包括瘦素在内的β稳定的，电荷中性的重子物质的EO，据信这在中子星的核心区域中实现。 [c]使用上述代码，我们确定了具有逼真的巴里昂 - 巴里昂相互作用的高密度重物物质的EOS，发现通过超子混合的效果，EOS变得太软而无法重现中子星的性能（质量和半径）。此外，我们提出了概括性的三 - 巴里孔力（ππ3bf），这是对三个核力量（ππ3NF）的两杆交换Δ机制的概括，并将ππ3bf应用于中子星物质。结果，发现ππ3bf提供了有吸引力的贡献并进一步软化了EOS。然后，我们对现象学短距离三范 - 巴里昂（Short-3bf）进行了编码，该力是从引入的短距离三核力力延伸的，以重现核物质的对称能量。我们发现，短-3bf使EOS僵硬，EOS合理地重现了中子星的质量ANS半径。