Magnetic Moments of Proton Drip-Line Nuclei and Abnormal Breaking of Isospin Symmetry

质子滴线核的磁矩与同位旋对称性的异常破缺

基本信息

批准号：
07640407
负责人：
FUKUDA Mitsunori
金额：
$ 1.54万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640407/
关键词：
Nuclear magnetic moment Proton rich nuclei Spin expectation value Nucleon density distribution 磁気モーメントアイソスピン対称性 Knight shift 高温超伝導

项目摘要

We have determined the nuclear magnetic moments of ^9C, ^<113>Q, ^<19>Q, and 21F.As a result, the abnormal behavier of magnetic moments seen in ^9C-^<13>0 pair, i.e. the abnormal spin expectation value or the unusual g-factor correlation, was not seen in the mirror pair of ^<13>0-^<13>B, For the cases of ^<19>O and ^<21>F, discussions using mirror-pair analyses can not be made because the partner of ^<19>Q is absent and the magnetic moment of ^<21>Mg, the partner of ^<21>F, has not been known yet. However, comparisons with theoretical calculations for each nucleus are possible. The results of calculations with the shellmodel code OXBASH (int. psdMK, PW) are all in good agreement with the experimental values within a few % for ^<13>Q, ^<19>Q, and ^<21>F.This fact has made the irregularity of ^9C-^9Li pair stand out. Therefore that is an implication that the abnormality of ^9C-^9Li pair is not a common feature of isospin T = 3/2 mirror pairs and it is due to the special situation for ^9C-^9Li pair. There has not been a successful theory yet that well reproduces the abnormality of ^9C-^9Li pair. There are still three possiblities for ^9C-^9Li pair as follows. i) Isospin symmetry breaks, ii) pairing of the even-number nucleon group breaks largely, iii) effective g-factors of nucleons are largely renormalized. If we use the effective g-factors determined experimentally at the double closed shell, the spin expectation value for ^9C-^9Li is found to get a value near the theoretical calculation. This fact makes the above iii) attract an attention. Recent theoretical works with AMD or cluster models on the nuclear structure of the A=9 system developping intensively might give a key to this problem in the near future.

我们已经确定了 ^9c， ^<113> q， ^<19> Q和21f的核磁矩。对于 ^<19> o和 ^<21> F的情况，在 ^<13> 0 - ^<13> b的镜像对中没有看到异常的自旋期望值或异常的G因子相关性，使用无法进行镜像对分析，因为 ^<19> q的伴侣是 ^<11> mg的磁矩， ^<21> F的伴侣的磁矩尚不清楚。但是，可以与每个核的理论计算进行比较。使用ShellModel Code Oxbash（int。PSDMK，PW）计算的结果与 ^<13> q， ^<19> q的几个％的实验值均吻合，并且 ^<21> f.事实使 ^9c- ^9li对的不规则性脱颖而出。因此，这意味着 ^9c- ^9li对的异常不是isospin t = 3/2镜对的常见特征，这是由于 ^9c- ^9li对的特殊情况所致。尚未有一个成功的理论，可以很好地再现 ^9c- ^9li对的异常。 ^9c- ^9li对仍有三个可能的可能性。 i）isospin对称性断裂，ii）偶数核子组的配对很大程度上，iii）核子的有效G因子在很大程度上被重新归一化。如果我们使用在双闭合壳体上实验确定的有效G因子，则发现 ^9c- ^9Li的自旋期望值接近理论计算。这一事实使上述iii）引起人们的注意。与AMD或群集模型有关A = 9系统的核结构的最新理论工作可能在不久的将来可能为此问题提供关键。