New Aspects of Nuclear Deformation

核变形的新方面

• 批准号: 06044249
• 负责人: OTSUKA Takaharu
• 金额: --
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Overseas Scientific Survey.
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06044249/
• 关键词: Interacting Boson Model; phonon; rotational damping; g-factor; Pd; Xe; Cs; Cs

In this research project, nuclear quadrupole and octupole deformations have been studied from various new aspects, including both dynamical and static deformations. The theoretical tool we have used is the Interacting Boson Model (IBM). The gamma-unstable deformation is known for Xe and Ba nuclei with the mass number -130, and is described by the O (6) limit of the IBM.The O (6) limit has been considered, in a classical term, as a gamma-unstable rotor. We, however, discovered an alternative picture where all eigenstates of the O (6) limit can be constructed as multiphonon states. This new approach is called the Q-phonon scheme. The phonons are excited on the top of a deformed equilibrium in this scheme. This scheme looks quite powerful in describing states even away from the O (6) limit. For instance, yrast odd-spin states can be described as Q-phonon states except for a singular point. The quantum chaos has been further studied in terms of the rotational damping and the width. We obtained a reasonable estimate of the width, and discussed branching numbers, etc. The octupole deformation has been studied with particular attention to the electric dipole transitions. The Interacting Boson-Fermion Model-2 has been used to analyze the g factors and M1 excitaion with respect to even-even Pd isotopes and odd-A rare-earth nuclei. Several odd-A Xe-Cs nuclei have been studied in terms of the Interacting Boson-Fermion Model-2, and a good agreement between experiment and calculation has been obtained.

在本研究计划中，我们从各种新的角度研究了核四极和八极形变，包括动态形变和静态形变。我们使用的理论工具是相互作用玻色子模型（IBM）。质量数为-130的Xe和Ba核的γ不稳定变形是已知的，并且由IBM的O（6）极限描述。O（6）极限在经典术语中被认为是γ不稳定的转子。然而，我们发现了另一种情况，即O（6）极限的所有本征态都可以构造为多声子态。这种新方法被称为Q声子方案。在这个方案中，声子被激发在变形平衡的顶部。这个方案在描述状态时看起来非常强大，甚至远离O（6）极限。例如，除了奇点之外，yrast奇自旋态可以被描述为Q声子态。从转动阻尼和宽度两个方面进一步研究了量子混沌。我们得到了一个合理的宽度估计，并讨论了分支数等八极形变已特别注意的电偶极跃迁进行了研究。本文用相互作用玻色子-费米子模型2分析了奇偶Pd同位素和奇A稀土核的g因子和M1激发。利用相互作用玻色子-费米子模型-2对几个奇A Xe-Cs核进行了研究，实验与计算取得了良好的一致。

项目成果

A.Gelberg, T.Otsuka and P.von Brentano: "Pairing Multiplets in Nuclei with O (6) Dynamic Symmetry" Physical Review C. 51. 147-151 (1995)

A.Gelberg、T.Otsuka 和 P.von Brentano：“原子核中的多重态与 O (6) 动态对称性配对”物理评论 C. 51. 147-151 (1995)

N.Pietralla,P.von Brentano T.Otsuka and R.F.Casten: "Odd-Spin Yrast States as Multiple Quadrupole-Phonon Excitations" Physics Letters B. (in press). (1995)

N.Pietralla、P.von Brentano T.Otsuka 和 R.F.Casten：“作为多重四极声子激发的奇自旋 Yrast 态”《物理快报 B》（正在出版）。

N.Pietralla, P.von Brentano, R.F.Casten, T.Otsuka and N.V.Zamfir: "Distributior of Low-Lying Quadrupole Phonon Strength in Nuclei" Physical Review Letters. 73. 2962-2965 (1994)

N.Pietralla、P.von Brentano、R.F.Casten、T.Otsuka 和 N.V.Zamfir：“原子核中低位四极声子强度的分布”物理评论快报。

A.Gelberg,T.Otsuka and P.von Brentano: "Pairing Mutliplets in Nuclei with 0(6) Dynamic Symmetry" Physics Review C. 51. 147-151 (1995)

A.Gelberg、T.Otsuka 和 P.von Brentano：“将原子核中的 Mutliplets 与 0(6) 动态对称性配对”物理评论 C. 51. 147-151 (1995)

T.Otsuka,K.-H.Kim,N.V.Zamfir and R.F.Casten: "A Theorem Relating E2 Matrix Elements between Collective States of Deformed Nuclei" submitted to Physics Letters B.

T.Otsuka,K.-H.Kim,N.V.Zamfir 和 R.F.Casten：“A Theorem Relation E2 Matrix Elements Between Collective States of Deformed Nuclei” 提交给《Physics Letters B》。