Precision mass measurement of lightweight self-conjugate nucleus 80Zr
Precision mass measurement of lightweight self-conjugate nucleus 80Zr
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DOI：
10.1038/s41567-021-01395-w
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发表时间：
2021-11
期刊：
影响因子：
19.6
通讯作者：
A. Hamaker;E. Leistenschneider;R. Jain;G. Bollen;S. Giuliani;K. Lund;W. Nazarewicz;L. Neufcourt
中科院分区：
文献类型：
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作者：
A. Hamaker;E. Leistenschneider;R. Jain;G. Bollen;S. Giuliani;K. Lund;W. Nazarewicz;L. Neufcourt
原子核中的质子和中子在类似于原子电子壳层结构的壳层中移动。核壳层结构由于核平均场随中子数 N 和质子 Z 的变化而变化，并且可以通过测量原子核之间的质量差异来探测这些变化。 N=Z= 40 自共轭核 80Zr 特别令人感兴趣，因为其质子和中子壳层结构预计非常相似，并且其基态高度变形。在这里，我们通过 80-83Zr 的高精度潘宁阱质量测量，为 80Zr 中变形双壳封闭的存在提供了证据。我们的质量值表明 80Zr 轻得多，因此比预测的束缚更牢固。这可以归因于 N=Z= 40 处变形的壳闭合和大的维格纳能量。采用多个全局核质量模型的统计贝叶斯模型混合分析表明，使用当前理论再现观测到的质量异常存在困难。
Protons and neutrons in the atomic nucleus move in shells analogous to the electronic shell structures of atoms. The nuclear shell structure varies as a result of changes in the nuclear mean field with the number of neutronsNand protonsZ, and these variations can be probed by measuring the mass differences between nuclei. TheN=Z= 40 self-conjugate nucleus80Zr is of particular interest, as its proton and neutron shell structures are expected to be very similar, and its ground state is highly deformed. Here we provide evidence for the existence of a deformed double-shell closure in80Zr through high-precision Penning trap mass measurements of80–83Zr. Our mass values show that80Zr is substantially lighter, and thus more strongly bound than predicted. This can be attributed to the deformed shell closure atN=Z= 40 and the large Wigner energy. A statistical Bayesian-model mixing analysis employing several global nuclear mass models demonstrates difficulties with reproducing the observed mass anomaly using current theory.