Project/Area Number  04640284 
Research Category 
GrantinAid for Scientific Research (C).

Research Field 
核・宇宙線・素粒子

Research Institution  The University of Tokyo 
Principal Investigator 
W・H・BENTZ 東京大学, 理学部, 助手
BENTZ Wolfgang The University of Tokyo, Graduate School of Science Research Associate, 大学院・理学系研究科, 助手 (20168769)
W.H.BENTZ 東京大学, 理学, 助手

CoInvestigator(Kenkyūbuntansha) 
田中 和廣 理化学研究所, 基礎科学特別研究員
YAZAKI Koichi The University of Tokyo, Graduate School of Science Professor, 大学院・理学系研究科, 教授 (60012382)

Project Fiscal Year 
1992 – 1993

Project Status 
Completed(Fiscal Year 1993)

Budget Amount *help 
¥1,500,000 (Direct Cost : ¥1,500,000)
Fiscal Year 1993 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1992 : ¥700,000 (Direct Cost : ¥700,000)

Keywords  Chiral Quark Model / Nuclear Structure / Faddeev Equation / Mean Field Approximation / Many Body Problem / カイラルクォーク模型 / 核子の構造 / Faddeev方程式 / 平均場近似 / 多体問題 
Research Abstract 
The research was carried out along the following three lines : First, we used effective quark theories based on QCD to investigate the internal quark structure of baryons in the mean field approximation. We found that in the simplest NambuJonaLasinio (NJL) model there exist no stable soliton solutions. If we extend the model to flavor SU(3), the instanton induced 6Fermi interaction plays the dominant role to stabilize the soliton against collapse. In this way we could describe both meons and baryons within the same model. We also investigated the chiral sigma model, and developed a method to eliminate the Landaughost from the soliton. Second, we solved the relativistic 3quark Faddeev equation in the NJL model exactly, including the J=0 and J=2 two body channels. This is the most important achievement of the present research. We have shown that with the original NJL Lagrangian one cannot obtain a bound state, and we have given the form of the Lagrangian by which one can describe the pion in the BetheSalpeter framework, and nucleon and delta in the Faddeev framework. We used the solution of the Faddeev equation to describe static properties of the nucleon, and found that the results of the naive quarkdiquark model are close to the exact ones provided that the quarkdiquark binding energy is small. Third, we investigated the equation of state of nuclear and neutron matter in the framework of relativistic mesonnucleon theory. Using the 1/N expansion, we have shown the importance of the higher order correlation terms to soften the equation of state. We have found that the softening of the relativistic equation of state holds over a wide range of temperatures and densities.
