Study of high energy nuclear reactions based on quantum chromodynamics
Project/Area Number  05640330 
Research Category 
GrantinAid for Scientific Research (C).

Research Field 
素粒子・核・宇宙線

Research Institution  The University of Tokyo 
Principal Investigator 
YAZAKI Koichi The University of Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (60012382)

CoInvestigator(Kenkyūbuntansha) 
BENTZ Wolfgang The University of Tokyo, Graduate School of Science, Research Associate, 大学院・理学系研究科, 助手 (20168769)

Project Fiscal Year 
1993 – 1995

Project Status 
Completed(Fiscal Year 1995)

Budget Amount *help 
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1995 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1994 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1993 : ¥800,000 (Direct Cost : ¥800,000)

Keywords  NJL model / mean field approach / Faddeev approach / pion exchange / nuclear transparency / color transparency / relativistic harmonic oscillator model / Hdibaryon / 南部・ジョナラジニオ模型 / 平均場近似 / Faddeev 方程式 / パイオン交換 / 核の透明度 / 相対論的調和振動子模型 / Hダイバリオン / NJL模型 / 相対論的Faddeev方程式 / colar transparency / 核子の内部構造 / Faddeev方程式 / 核透明度 / グラウバー近似 / モンテ・カルロ法 / クォーク・クラスター模型 / 南部・ジョナラジニオ模型 
Research Abstract 
High energy nuclear reaction has two aspects, one related to perturbative QCD through elementary processes at large momentum transfers and the other related to non perturbative QCD through the internal structure of participating hadrons and their initial and final state interactions. In this research project, the Nambu Jona Lasino model has been studied as a relativistic model of the nucleon internal structure. The nuclear transparency which is a measure of initial and final state interactions and the Hdibaryon in nuclear matter have been also studied as means of observing the internal structure in high energy reactions. In the study of the NJL model, we have calculated the quark scalar density, the axial vector coupling constant and the magnetic moment of the nucleon in order to examine the properties of the solution for th relativistic Faddeev equation and confirmed that the observed properties of the nucleon are globally reproduced. We have also made a comparison between the three
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quark picture based on the Faddeev approach and the soliton picture based on the mean field approach. It has been found that the inclusion of the twobody correlation in the mean field approach may solve the longstanding problem about the stability of the solution and the pion exchange between the quarks gives an important contribution in the Faddeev approach. As for the nuclear transparency, the relativistic effect has been found to suppress the expansion rate of the proton squeezed by the large momentum transfer and play an essential role in the color transparency. A relativistic harmonic oscillator quark model has been used to study the above suppression. The extension of the study to the cases of hadronic quasielastic processes such as (p, 2p) and (pi, pi'p) are under way. Hdibaryon in nuclear matter has been studied by the Brueckner theory based on the Hnucleon interaction we obtained previously and the effective mass and the well depth have been calculated. The effects of HLAMBDALAMBDA coupling have been also examined. Less

Report
(5results)
Research Output
(30results)