1989 Fiscal Year Final Research Report Summary
Study of Structure of Light Extremely Neutron-Rich Nuclei and Their Anomalous Properties
| Project/Area Number |
63540209
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
核・宇宙線・素粒子
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| Research Institution | Niigata University |
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Principal Investigator |
IKEDA Kiyomi Niigata University, Faculty of Science, Professor, 理学部, 教授 (40011548)
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| Project Period (FY) |
1988 – 1989
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| Keywords | 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 |
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| Research Abstract |
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.
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