Project/Area Number  10044059 
Research Category 
GrantinAid for Scientific Research (B).

Section  Joint Research . 
Research Field 
素粒子・核・宇宙線

Research Institution  The University of Tokyo 
Principal Investigator 
OTSUKA Takaharu Graduate School of Science, The University of Tokyo, Professor, 大学院・理学系研究科, 教授 (20201379)

CoInvestigator(Kenkyūbuntansha) 
ISACKER Piet 国立重イオン加速器研究所, 研究員
BROWN Alex B ミシガン州立大学, サイクロトロン研究所, 教授
HONMA Michio Center for Mathematical Sciences, University of Aizu, Lecturer, コンピュータ理工学部, 講師 (40264569)
MIZUSAKI Takahiro Graduate School of Science, The University of Tokyo, Research Associate, 大学院・理学系研究科, 助手 (50251400)

Project Fiscal Year 
1998 – 1999

Project Status 
Completed(Fiscal Year 1999)

Budget Amount *help 
¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1999 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Fiscal Year 1998 : ¥1,900,000 (Direct Cost : ¥1,900,000)

Keywords  shell model / Monte Carlo Shell Model / pf shell / effective interaction / Interacting Boson Model / Boson / Octupole deformation / f boson / 殻模型 / モンテカルロ殻模型 / pf殻 / 有効相互作用 / 相互作用するボソン模型 / ボソン / 八重極変形 / fボソン / 量子モンテカルロ対角化法 / 不安定核 / ペアリング / IBM4 / 2p2h励起 / 4p4h励起 
Research Abstract 
The structure of unstable nuclei near N=Z line is studied theoretically in this research project. The work has been carried out in collaboration with Professor B.A. Brown of Michigan State University and Dr. Piet Van isacker of GANIL. Various results have been obtained. Among those, the most prominent result is the determination of an effective nucleonnucleon interaction for fun pfshell calculations. Such calculations have been impossible practically, and have become feasible by Monte Carlo Shell Model. We have obtained a universal interaction so that even midshell nuclei can be well described with a good accuracy. This work has been done in collaboration with Prof. Brown. With Dr. Van Isacker, we have investigated effective interaction for the model space between N=Z=28 and 40 or 50. The validity of the space is also discussed in connection to the Interacting Boson Model. In addition, the spdf boson model is studied with many new algebraic formulas. The structure of nuclei with N or Z=28 is studied as possible candidates of semimagic nuclei. The coexistence of spherical and deformed states is of particular interest. The Monte Carlo Shell Model played a crucial role.
