Study of compactification in superstring and low energy effective theories

作为超弦低能有效理论的超对称模型的现象学特征已经从不同的角度进行了研究。本课题取得的主要成果如下：1。如果我们引入某种可以解决著名的双三重态分裂问题的对称性，那么在规范中介超对称破缺的框架下，高规子的质量就是非普适的。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谱。我们指出这一光谱的特征受到μ问题的青睐。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电火花放电。我们证明了高介子质量中的CP相可以以一种抵消其他贡献的方式贡献这些edm。在这种情况下，可以允许在超对称破缺参数中存在较大的CP相位。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希格斯玻色子的可能性。我们建立了一个中微子模型，它可以成功地实现轻生现象。我们证明，如果我们建立了一个能实现最大CP不对称且满足中微子振荡实验约束的模型，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问题相关的平面方向建立了重子发生和暗物质的模型。

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.