Shape coexistence in the N=19 neutron-rich nucleus 31Mg explored by β-γ spectroscopy of spin-polarized 31Na
Shape coexistence in the N=19 neutron-rich nucleus 31Mg explored by β-γ spectroscopy of spin-polarized 31Na
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通过自旋极化 31Na 的 β-γ 能谱探索 N=19 富中子核 31Mg 中的形状共存
DOI：
10.1016/j.physletb.2017.01.049
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
M.Kimura
中科院分区：
文献类型：
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作者：
H.Nishibata;T.Shimoda;A.Odahara;S.Morimoto;S.Kanaya;A.Yagi;H.Kanaoka;M.R.Pearson;C.D.P.Levy;M.Kimura
利用自旋极化31 Na的β -γ能谱研究了中子幻数N= 20的“反转岛”区域内富中子31 Mg核的激发态结构。在中子分离能低于2.3 MeV的31个Mg能级中，所有5个正奇偶能级的自旋值都是通过观察各向异性β衰变确定的。根据能级的自旋和能量，提出了两个K π= 1/2+和1/2 -的旋转带。用反对称分子动力学（AMD）加生成坐标法（GCM）对实验结果和理论计算进行了逐级比较。发现在31 Mg的低激发能区多种核结构共存。
The structure of excited states in the neutron-rich nucleus 31 Mg, which is in the region of the “island of inversion” associated with the neutron magic number N= 20, is studied by β–γ spectroscopy of spin-polarized 31 Na. Among the 31 Mg levels below the one neutron separation energy of 2.3 MeV, the spin values of all five positive-parity levels are unambiguously determined by observing the anisotropic β decay. Two rotational bands with K π= 1/2+ and 1/2− are proposed based on the spins and energies of the levels. Comparison on a level-by-level basis is performed between the experimental results and theoretical calculations by the antisymmetrized molecular dynamics (AMD) plus generator coordinate method (GCM). It is found that various nuclear structures coexist in the low excitation energy region in 31 Mg.