arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2307.04656nucl-th
收藏

原子核同位旋混合的两能级模型计算新方法

A new approach to two-level model calculation of isospin mixing in nuclei

Sukhendusekhar Sarkar

备注：
6 pages, no figure
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

AI总结：

本文提出一种基于未微扰能级定位的两能级模型新方法，利用实验与壳模型数据计算自共轭核的同位旋混合概率，并在$^{24}Mg$中发现迄今最大的同位旋混合。

摘要：

针对孤立两能级模型，提出了一种计算原子核同位旋混合概率的新方法，克服了通常采用同位旋标量核哈密顿量的壳模型结果的常见局限性。该方法基于在混合前定位混合双重态的未微扰能级。利用与原子核中一个双重态或两对双重态相关的实验能级和壳模型能级、电磁/Gamow-Teller跃迁矩阵元，计算了七个自共轭核的同位旋混合概率。这里考虑的四个自共轭核（P、S、Cl、Ar）显示出大的同位旋混合矩阵元和所观测同位旋混合双重态对的大的未微扰能隙。在$^{24}Mg$中观测到的分别位于9828.11 keV和9967.19 keV的双重态（$1^{+},1^{+}$）中发现了大的同位旋混合（31.40-48.76%）。这可能是迄今在原子核中发现的最大同位旋混合。这远大于最近在$^{26}$Si中发现的$({20}_{-9.904}^{+9.142}$%)。该方法具有足够的普适性，可应用于其他两能级/多能级混合问题，特别是可能有助于在费米贝塔衰变背景下考虑同位旋混合。

英文摘要：

A new method has been proposed for isolated two-level model to calculate isospin mixing probability in nuclei overcoming common limitations of usual shell model results with isoscalar nuclear Hamiltonian. The method is based on locating the unperturbed levels of the mixed doublet before mixing. Experimental and shell model level energies, electromagnetic/Gamow-Teller transition matrix elements associated with a doublet or two doublet pairs in a nucleus are used to calculate isospin mixing probability in seven self-conjugate nuclei. The four self-conjugate nuclei (P, S, Cl, Ar) considered here show large isospin mixing matrix elements and large unperturbed energy-gaps of the observed isospin-mixed doublet pairs. Large isospin mixing (31.40-48.76 %) is found in the observed doublet ($1^{+},1^{+}$) at 9828.11 and 9967.19 keV, respectively, in $^{24}Mg$. This is probably the largest isospin mixing ever found in a nucleus. This is much larger than that $({20}_{-9.904}^{+9.142}$%) has been found recently in $^{26}$Si. The method is general enough to be applicable to other two-level/multi-level mixing problems and in particular, might be useful for consideration of isospin mixing in the context of Fermi beta decay also.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑