Nuclear structure at extreme

极端核结构

基本信息

批准号：
10044339
负责人：
YAZAKI Koichi
金额：
--
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for International Scientific Research.
财政年份：
1998
资助国家：
日本
起止时间：
1998 至无数据
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10044339/
关键词：
Isospin beta stability line stable nucleus unstable nucleus closed shell 32Mg magic number Monte Carlo shell model 高スピン状態高アイソスピン状態量子モンテカルロ対角化法トレント ect 極限状態原子核構造殻模型

项目摘要

In this research project, the nuclear structure has been studied at variousextremes. We first investigated the structure of nuclei at high isospin. High isospin indicates situations that the neutron number is greater than theproton number or vice versa. The z-component of isospin is given by (Z-N)/2 where Z and N mean the proton and neutron numbers, respectively. The magnitude of isospin, T, should be larger than or equal to Tz. In nuclei with equal numbers of neutrons and protons, Tz=0, and the ground and low-lying states are of T0. Low-isospin corresponds to the nuclei on and near the beta stability line (stable nuclei) where the proton and neutron numbers are equal or close to each other. On the other side, nuclei with large T are far from the beta stability line, being called unstable nuclei. It has been clarified during the past ten years that unstable nuclei have structure very different from the structure of stable nuclei. In this project, we studied 32Mg, which is an example of unstable nuclei, and its vicinity. The N20 is a magic number as well known. Therefore, on the standpoint of stable nuclei, 32Mg should be a neutron-closed nucleus, and should have a spherical ground state. This has been shown to be incorrect, experimentally and theoretically. On the contrary, studies on nuclei around 32Mg have hardly been done. We can now, however, carry out such studies by using the Monte Carlo shell model being developed by the group of the University of Tokyo. By such studies, it has been clarified that the change from stable nuclei does not occur suddenly at a certain nucleus but does occur gradually, and that the monopole component of the effective interaction plays a crucial role in this. In addition to the above studies, the spherical-deformed transition has been studied including high spin states.

在这个研究项目中，对核结构进行了各种极端的研究。我们首先研究了高同位旋的原子核结构。高同位旋表示中子数大于质子数的情况，反之亦然。同位旋的 z 分量由 (Z-N)/2 给出，其中 Z 和 N 分别表示质子数和中子数。同位旋的大小 T 应大于或等于 Tz。在中子数和质子数相等的原子核中，Tz=0，基态和低态为T0。低同位旋对应于 β 稳定线及其附近的原子核（稳定核），其中质子数和中子数彼此相等或接近。另一方面，T较大的原子核远离β稳定线，称为不稳定原子核。在过去的十年里，人们已经阐明不稳定原子核的结构与稳定原子核的结构非常不同。在这个项目中，我们研究了 32Mg（不稳定原子核的一个例子）及其附近区域。 N20 是一个众所周知的神奇数字。因此，从稳定原子核的角度来看，32Mg应该是一个中子闭核，并且应该具有球形基态。这在实验和理论上都被证明是不正确的。相反，对32Mg附近的原子核的研究却很少。然而，我们现在可以使用东京大学小组开发的蒙特卡罗壳模型来进行此类研究。通过这些研究，已经阐明，在某个核处，稳定核的变化并不是突然发生的，而是逐渐发生的，有效相互作用的单极子分量在其中起着至关重要的作用。除了上述研究之外，还研究了包括高自旋态的球形变形跃迁。