Theoretical Study of Particles and Fields

该项目的主要目的是了解自然界的基本组成及其性质，以及粒子物理学的基本理论框架。为此，藤川和山田一起研究了夸克的手征结构，特别是顶夸克。根据正负电子湮灭的实验数据，我们已经证明顶夸克的手征结构是相当准确的。受此分析的启发，藤川还研究了夸克和轻子的模型及其手征结构。T.Eguchi与他的合作者一起澄清了与超对称规范理论动力学相关的基本问题。分析了有无物质的超对称杨-米尔斯理论的共形性质。同时，结合弦理论的观点，阐明了四维、三维和五维时空中的场论性质。他还研究了几个基本问题有关的弦理论和量子引力。T.柳田连同他的合作者研究了各个方面的超对称扩展的标准模型。特别是，他对大统一方案中的等级问题进行了分析。他提出了一个可能的方案，这个方案最终可能解决为什么在当前能量下的物理学和在大统一尺度下的物理学可以统一在一个自然的理论框架中，而不会引起大的质子衰变。他还分析了超对称性破缺机制的基本问题，需要强调的是，CERN的来访者给我们的理论小组提供了极大的启发。

The major purpose of this project is to understand the basic constituents of the Nature and their properties, together with the basic theoretical framework of particle physics.For this purpose, Fujikawa together with Yamada studied the chiral structure of quarks, in particular, the top quark. On the basis of the experimental data from electron-positron annihilation, it has been shown that the chiral structure of the top quark holds quite accurately. Motivated by this analysis, Fujikawa also studied a model of quarks and leptons and their chiral structure.T.Eguchi together with his collaborators clarified the basic issues related to the dynamics of supersymmetric gauge theories. The conformal properties of supersymmetric Yang-Mills thoeries with or without matters have been clearly analyzed. Also, some of field theoretical properties in 4 as well as 3 and 5 dimensional space-time have been clarified by incorporating the string theoretical view point. He also studied several fundamental issues related to string theory and quantum gravity.T.Yanagida together with his collaborators studied various aspects of super-symmetric extension of the standard model. In particular, he made an analyis related to the issue of the hierarchy problem in the grand unification scheme. He put forward a possible scheme which may eventually solve why the physics at the present energies and the physics at the grand unification scale can be unified in a natural theoretical framework, without inducing large proton decay. He also analyzed the basic issue of supersymmetry breaking mechanism.It should be emphasized that the visitors from CERN provided extremely stimulative information to our theory group.