Study of supersymmetric unified theory based on superstring theory

从不同角度研究了作为超弦低能有效理论的有效超引力模型的特点。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。还研究了非通用软破裂参数所带来的唯象问题。在这些研究中，我们发现分级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性的影响，以及软破缺参数中出现的CP相与中子电偶极矩之间的关系。作为结果，我们发现可能会有新的唯象可能性，这些可能性在通常的普遍软超对称破缺中是没有发现的。我们还研究了软超对称性破缺参数的风味结构，并推导出和ru…2.我们考察了超弦有效模型中经常出现的具有额外U(1)对称性和规范单重场的模型的各种唯象特征。特别是，在这些研究中，我们专注于能够实现小中微子质量的模型。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‘质量的关系。我们发现，与额外U(1)相关的D项平坦方向可能会对膨胀宇宙论产生有趣的影响。我们构建了一个能够以自然方式保证质子稳定性的模型。在这样的模型中，我们发现有可能实现同时解释太阳中微子问题、大气中微子问题和暗物质的中微子质量分级。这些结果是我们项目开始时旨在研究的课题的重要部分。我们已经在会议上发表了这些成果，并发表在期刊上。较少

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