Study of supersymmetric unified theory based on superstring theory

从多个角度研究了作为超弦低能有效理论的有效超重力模型的特征。本课题取得的主要成果如下：1。研究了有效超引力模型中出现的软超对称破缺参数的一般特征。本文还研究了非普适软破参数所带来的现象学问题。在这些研究中，我们发现分层软标量质量是可以实现的。我们还研究了这些软标量质量对规范耦合统一的影响，以及软断裂参数中出现的CP相与中子电偶极矩的关系。作为结果，我们发现可能存在在通常的普遍软超对称破缺中没有发现的新的现象学可能性。我们还研究了软超对称破缺参数的风味结构，并推导了它们的和。我们研究了在超弦有效模型中经常出现的额外U(1)对称性模型和规范单重场的各种现象学特征。特别是在这些研究中，我们把精力集中在可以实现小中微子质量的模型上。在重整化群方程的基础上，研究了辐射对称性破缺与额外Z质量之间的关系。我们发现，与额外的U(1)相关的d项平坦方向可能对暴胀宇宙学产生有趣的影响。我们建立了一个能保证质子自然稳定的模型。在这个模型中，我们发现有可能实现分层中微子质量，从而同时解释太阳中微子问题、大气中微子问题和暗物质问题。这些结果是我们课题的重要组成部分，在这个项目开始的时候，我们就打算研究这些课题。我们已经在会议上发表了这些结果，并在期刊上发表了这些结果。少

The features of effective supergravity models derived as the low energy effective theory of superstring have been studied from various points of view. The main results obtained in this project are followings.1.The general features of soft supersymmetry breaking parameters which appear in the effective supergravity models have been studied. The phenomenological aspects brought by the nonuniversal soft breaking parameters have also been investigated. In these studies we found that the hierarchical soft scalar masses could be realized. We also examined how these soft scalar masses affect the gauge coupling unification and the relation between the CP phases appeared in soft breaking parameters and the electric dipole moment of neutron. As the results we found that there could be new phenomenological possibilities which have not been found in the usual universal soft supersymmetry breaking. We also studied the flavor structure of the soft supersymmetry breaking parameters and derived sum ru … More les for them.2.We have examined the various phenomenological features of models with extra U (1) symmetries and gauge singlet fields which often appeared in the effective models of superstring. Especially, in these studies we concentrated ourselves to the models which could realize the small neutrino masses. The study of the relation between the radiative symmetry breaking and the extra Z' mass has been done on the basis of the renormalization group wquations. We found that the D-term flat direction associated with the extra U (1) could have interesting effects on the inflation cosmology. We constructed a model which could guarantee the proton stability in the natural way. In such a model we found that it was possible to realize the hierarchical neutrino masses which could explain the solar neutrino problem, the atmospheric neutrino problem and dark matter simultaneously.These results are important parts of our subjects which were aimed to study at the beginning of this project. We have already presented these results as the talks in the conferences and also published in the journals. Less