Project/Area Number  05640351 
Research Category 
GrantinAid for Scientific Research (C).

Research Field 
素粒子・核・宇宙線

Research Institution  HIROSHIMA UNIVERSITY 
Principal Investigator 
KODAIRA Jiro Hiroshima University, Department of Physics Associate Professor, 理学部, 助教授 (40127080)

CoInvestigator(Kenkyūbuntansha) 
ONOGI Tetsuya Hiroshima University, Department of Physics Research Associate, 理学部, 助手 (70211802)
MUTA Taizo Hiroshima University, Department of Physics Professor, 理学部, 教授 (80025353)

Project Fiscal Year 
1993 – 1994

Project Status 
Completed(Fiscal Year 1994)

Budget Amount *help 
¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1994 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1993 : ¥400,000 (Direct Cost : ¥400,000)

Keywords  Standard Model / Field Theory / Radiative Correction / QCD / Symmetry Breaking / 標準模型 / 場の理論 / 輻射補正 / 量子色力学 / 対称性の破れ / 対称性の自発的破れ 
Research Abstract 
The aim of this project is to investigate the quantum effects in various models as well as theoretical problems involved. The gammagamma collider is an interesting idea since there are processes which reveal the self couplings of gauge fields at the tree level. So in view of experimental feasibility, we propose a method to measure the beam polarizations and the luminosity of gammagamma colliders. We examine also the radiative corrections to the mass of the lightest Higgs boson in the minimal supersymmetric standard model. We find that the higher order corrections to the Higgs boson mass are nonnegligible. Before considering new models, it is necessary to understand fully the quantum effects in the standard model. However the higher order calculation is so complicated and difficult. It seems that a calculational method which keeps the gauge invariance at each stage of calculation is helpful. We show that the background field method is a simple way of deriving the same gauge invariant results which are obtained by the pinch technique. We next apply the pinch technique to the process e^gamma*W^upsiron to study the effects of the higherorder corrections to WWgamma three gauge boson vertex. The spin dependent quantities may prvide us with useful information. So, we investigate the spin structure of nucleons. The twist3 operators are carefully examined and their relations are revealed. We also study the dynamical origin of CP violation in electroweak theory in the context of the composite Higgs models. The phase structure of fourfermion theories is also investigated with spacetime curvature, temperature and chemical potentials. 動的対称性の破れから、どの様な現象が示唆されるかについても考察した。ヒッグス粒子が複合粒子の場合、CP対称性が動的に破れる可能性があることが解った。一方、動的対称性の破れについての理論的考察として、様々な状況での4体フェルミ理論の相構造を考察した。
