Study of compactification in superstring and low energy effective theories

从不同的角度研究了超弦低能有效理论所导出的超对称模型的唯象特征。本课题取得的主要成果如下：1.如果我们引入一种对称性来解决著名的二重态-三重态分裂问题，那么在规范介导超对称破缺的框架下，高更诺的质量就变成非普适的。我们在SU（5）模型中研究了这方面的问题，并研究了超伴子的质量谱。我们指出，这种谱的特征是μ问题所偏爱的.一般来说，超对称破缺参数中的CP相会引起电子和中子的危险EDM。我们发现，CP阶段的质量的高金诺可以有助于这些EDM在这样一种方式，他们取消其他的贡献。在这种情况下，大CP相位可以允许在超对称性破缺参数。我们研究了超对称破缺参数的允许参数区域，并讨论了在这种情况下存在轻Higgs的可能性.我们构造了一个中微子模型，该模型可以成功地实现引力子问题的轻子生成。我们发现，如果我们构造一个能实现最大CP不对称性并满足中微子振荡实验约束条件的模型，再加热温度可以低于引力子问题所要求的温度.我们利用与μ问题相关的平坦方向构造了一个重子生成和暗物质的模型。

Phenomenological features of supersymmetric models derived as low energy effective theories of superstring have been studied from various points of view. Main results obtained in this project are followings.1. If we introduce a certain symmetry which may solve the famous doublet-triplet splitting problem, the mass of gauginos becomes nonuniversal in the framework of gauge mediation supersymmetry breaking. We studied this aspect in an SU(5) model and also the mass spectrum of superpartners. We pointed out that the feature of this spectrum was favored by the μ problem.2. In general CP phases in the supersymmetry breaking parameters induce dangerous EDM of an electron and a neutron. We showed that the CP phases in the mass of gauginos can contribute to these EDMs in such a way that they cancel other contributions. In that case large CP phases can be allowed in the supersymmetry breaking parameters. We studied allowed parameter regions of the supersymmetry breaking parameters and discussed the possibility of light Higgs in that case.3. We constructed a neutrino model which can realize successful leptogenesis escaping the gravitino problem. We showed that reheating temperature can be lower than the one which is required from the gravitino problem if we construct a model which realizes maximum CP asymmetry and satisfies constraints from neutrino oscillation experiments.4. We constructed a model for baryogenesis and dark matter by using a flat direction related to the μ problem.