Research of electromagnetic transitions and beta decays of unstable nuclei

不稳定核的电磁跃迁和β衰变研究

• 批准号: 13640262
• 负责人: YOSHINAGA Naotaka
• 金额: $ 0.32万
• 依托单位: Saitama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640262/
• 关键词: Nuclear Structure; Unstable nuclei; Electromagnetic transitions; Beta decay; Shell model; Pair model; 奇核; ペア近似

In the mass region around 130, interesting phenomena are found such as high-spin isomers, backbending phenomena, triaxial deformation, chiral bands. Moreover, these nuclei provide necessary information concerning the abundance of species which are made in supernovae explosions. The nuclei treated in this research are neither vibrational nor rotational nuclei, thus cannot be described in terms of mean field theories. We describe them in terms of the pair-truncated model which assumes angular momentum 0 and 2 collective pairs. In ^<132>Ba we have successfully reproduced ground state band, quasi-gamma band, and states in backbending region. The backbending is confirmed to be caused by the alignment of neutrons due to the magnetic dipole moment of 10^+ state. The similar study has been done for Xe isotopes, predicting the 10+ isomer just above the 8^+ state. In ^<132>La, the chiral band is predicted theoretically. However, we have predicted that two angular momenta by neutrons and protons are rather parallel than orthogonal. As a preliminary calculation, we have shown that our model has a predictive power for the beta decays as well.

在130左右的质量区，发现了一些有趣的现象，如高自旋异构体、后弯现象、三轴变形、手性带等。此外，这些原子核提供了有关超新星爆炸中产生的物种丰度的必要信息。本研究中处理的原子核既不是振动原子核，也不是旋转原子核，因此不能用平均场理论来描述。我们用对截断模型来描述它们，该模型假设角动量为 0 和 2 个集体对。在^<132>Ba中，我们成功地再现了基态能带、准伽马能带和后弯区域中的态。后弯被证实是由10^+态磁偶极矩导致的中子排列引起的。对 Xe 同位素也进行了类似的研究，预测 10+ 异构体略高于 8^+ 态。在^<132>La中，理论上预测了手性带。然而，我们预测中子和质子的两个角动量是平行的而不是正交的。作为初步计算，我们已经表明我们的模型对贝塔衰减也具有预测能力。

项目成果

K.Enami: "Generator coordinate method combined with exact triaxial spin projection"Physical Review C. 63. 044322-044335 (2001)

K.Enami：“与精确三轴自旋投影相结合的发生器坐标法”Physical Review C. 63. 044322-044335 (2001)

K.Enami, K.Tanabe, N. Yoshinaga: "Generator coordinate method combined with exact triaxial spin projection"Physical Review. C63. 044322-1-13 (2001)

K.Enami、K.Tanabe、N. Yoshinaga：“与精确三轴自旋投影相结合的发生器坐标法”物理评论。

K.Higashiyama: "Shell model study of backbending phenomena in Xe isotopes"Physical Review C. 65. 054317-054325 (2002)

K.Higashiyama：“Xe 同位素后弯现象的壳模型研究”Physical Review C. 65. 054317-054325 (2002)

K.Enami, K.Tanabe, N. Yoshinaga: "Quantum-number-projected generator coordinate method and the shell model"Physical Review. C65. 064308-1-14 (2002)

K.Enami、K.Tanabe、N. Yoshinaga：“量子数投影发生器坐标方法和壳模型”物理评论。

K.Enami: "Quantum-number-projected generator coordinate method analysis of low-lying states in ^<130,132>Xe"Physical Review C. 66. 047301-047305 (2002)

K.Enami：“^<130,132>Xe 中低洼态的量子数投影发生器坐标法分析”物理评论 C. 66. 047301-047305 (2002)