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

基本信息

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

项目摘要

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.

我们沿着该提案研究了三个主题：（i）研究富中子核结构的理论发展。 (ii)对^<11>Li的异常性质的理解。 (iii) 极富中子核中电偶极子模式的研究。关于第一主题，簇轨道壳模型，在参考文献中提出。 1 和 5 已被证明能够有效地描述富中子核这样的松散耦合系统，并成为中子滴线核 ^<11>Li 研究的基础（参考文献 7）。该模型预计适用于诸如参考文献中完成的原子核中α簇形成机制等问题。 3和9。在第二个主题中，我们首先在参考文献中展示。从图7中可以看出，^<11>Li的一些异常现象，例如极大的半径和中子晕的密度分布，在我们的模型中被成功理解，然后在参考文献中引入。图8中的簇模型观点是为了更好地描述解释^<11>Li结合机制所需的两个中子对相关性。对于第三个主题，我们在参考文献中检查了流体动力学和微观模型。图 2、4 和 6 显示极端富中子核的 E1 强度在低激发能下碎裂。由于我们已经很好地理解了 ^<11>Li 的基态特性，我们现在正在扩展簇轨道壳模型来寻找 ^<11>Li 中的软电偶极子模式。初步结果非常令人鼓舞，并且似乎解释了在使用放射性核束的高能重离子碰撞中观察到的电磁解离截面的增强。