Study of Structure of Light Extremely Neutron-Rich Nuclei and Their Anomalous Properties

轻极富中子核结构及其反常性质研究

• 批准号: 63540209
• 负责人: IKEDA Kiyomi
• 金额: $ 0.51万
• 依托单位: Niigata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63540209/
• 关键词: Neutron-Rich Nuclei; Neutron Halo; Neutron Dripline Nucleus ^<11>Li; Soft Electric Dipole Vibration; Coulomb Excitation; Radioactive Nuclear Beam; Cluster-Orbital Shell Model; Two-Neutron Pairing Correlation; 極度中性子過剰原子核; 中性子ハロ(暈)構造; 不安定原子核ビ-ム

We have studied three subjects along the proposal: (i) A theoretical development to study the structure of neutron-rich nuclei. (ii) The understanding of the anomalous properties of ^<11>Li. (iii) The investigation of the electric dipole mode in extremely neutron-rich nuclei. Regarding the first subject the cluster-orbital shell model, proposed in refs. 1 and 5, has proven to be powerful in describing such a loosely coupled system as neutron-rich nuclei and become a basis of the study of the neutron dripline nucleus ^<11>Li,(ref. 7). The model is expected to be applicable for such problems as the mechanism of alpha cluster formation in nuclei as done in refs. 3 and 9. In the second subject we have first shown in ref. 7 that some of the anomaly of ^<11>Li, e.g., the extremely large radius and the density distribution with the neutron halo, are successfully understood in our model and then introduced in ref. 8 the cluster model point of view in order to better describe the two-neutron pair correlation that is needed to explain the binding mechanism of ^<11>Li. For the third subject we have examined both hydrodynamical and microscopic models in refs. 2, 4, and 6 to show that the E1 strength of the extremely neutron-rich nuclei are fragmented at low excitation energy. Since we have understood the ground state properties of ^<11>Li fairly well, we are now extending the cluster-orbital shell model to look,for the soft electric dipole mode in ^<11>Li. A preliminary result is very encouraging and appears to account for the enhancement of the electromagnetic dissociation cross section observed in high-energy heavy-ion collisions using radioactive nuclear beams.

我们沿着这个建议研究了三个主题：(i)研究富中子核结构的理论发展。（ii） ^<11>Li异常性质的认识。（iii）极富中子核中电偶极子模式的研究。关于第一个主题，在参考文献中提出的簇-轨道壳模型。在描述富中子核这类松散耦合系统方面已被证明是强有力的，并成为中子滴线核研究的基础^<11>Li,（参考文献）。7）. 该模型有望适用于诸如参考文献中所做的核中α团簇形成机制等问题。3和9。在第二主题中，我们首先在参考文献7中表明，我们的模型成功地理解了^<11>Li的一些异常，例如，极大的半径和带有中子晕的密度分布，然后在参考文献8中引入了星团模型的观点，以便更好地描述解释^<11>Li的结合机制所需的双中子对相关性。对于第三个主题，我们研究了参考文献中的流体动力学和微观模型。2、4和6表明极富中子核的E1强度在低激发能下破碎。由于我们已经很好地理解了^<11>Li的基态性质，我们现在正在扩展团簇-轨道壳层模型来寻找^<11>Li中的软电偶极子模式。一个初步的结果是非常令人鼓舞的，并且似乎解释了使用放射性核束在高能重离子碰撞中观察到的电磁解离截面的增强。

项目成果

Y.Suzuki: "New Type of Dipole Vibration in Nuclei" Progress of Theoretical Physics. 83. 180-184 (1990)

Y.Suzuki：“新型原子核偶极子振动”理论物理进展。

Y.Suzuki: "Cluster-Orbital Shell Model with Continuum Discretization and Its Application to the He Isotopes" Physical Review C. 41. 736-743 (1990)

Y.Suzuki：“具有连续离散化的簇轨道壳模型及其在 He 同位素中的应用”物理评论 C. 41. 736-743 (1990)

Y.Tosaka: "Structure of Neutron-Halo in the Ground State of ^<11>Li" Progrese of Theoretical Physics. (1990)

Y.Tosaka：“^<11>Li基态中子晕的结构”理论物理进展。

Y. Tosaka: "Structure of ^<11>Li in the Cluster-Orbital Shell Model for the ^9Li+n+n System" Nuclear Physics A (1990).

Y. Tosaka：“^9Li n n 系统簇轨道壳模型中 ^<11>Li 的结构”核物理 A (1990)。

Y.Tosaka,: "Structure of Neutron-Halo in the Ground State of ^<11>Li" Progress of Theoretical Physics, to be published. (1990)

Y.Tosaka，：“^<11>Li基态中子晕的结构”，理论物理进展，待出版。