Exploration of physics beyond the standard model through flavor physics

1. 超对称模型中的味物理研究超对称被认为是极电子伏尺度下新物理的一个很有前途的候选者，寻找超对称粒子是大型强子对撞机实验的主要目标。如果超对称粒子在那里被发现，风味物理学将在探索GUT和/或跷跷板中微子尺度的理论方面发挥重要作用。我们计算了几个超对称模型中B衰变、K衰变和轻子风味破坏过程中的各种物理可观测量，并说明了如何通过比较风味信号来区分不同的模型。我们还计算了超对称模型中B介子的陶子衰变和半陶子衰变的分支比，并显示了这些量的测量与lhc中带电希格斯玻色子搜索之间的协同作用。左右对称模型中的轻子味违逆小质量中微子为标准模型之外的可能物理提供了重要线索。特别是，如果中微子质量产生的起源存在于ay尺度，我们可以预期在大型强子对撞机上发现新的粒子，以及轻子风味破坏过程的大幅增强。作为一个例子，我们在左右对称模型中研究了tau和μ子轻子风味违反过程与中微子质量产生机制之间的关系。本文指出，如果用t宇称扩展小希格斯模型，则该模型可以容纳暗物质粒子。我们在这个模型中研究了现象学约束和暗物质遗迹丰度，并研究了在这些约束下探测银河系暗物质粒子对湮灭的宇宙正电子信号的可能性。

1. Study of flavor physics in supersymmetric modelsSupersymmetry is considered to be a promising candidate of new physics at the TeV scale, and search for supersymmetric particles is a main target of LHC experiments. If supersymmetric particles are discovered there, flavor physics will play an important role in probing theory at the GUT and/or the seesaw neutrino scale. We have calculated various physical observable quantities in B decays, K decays and lepton flavor violation processes for several supersymmetric models, and have illustrated how we can distinguish different models by comparing flavor signals. We have also calculated branching ratios of tauonic decays and semi tauonic decays of B mesons in supersymmetric models and show synergy between measurements of these quantities and charged Higgs boson search at LHC.2. lepton flavor violation in the left-right symmetric modelSmall masses of neutrinos provide an important clue to possible physics beyond the standard model. In particular, if the origin of the neutrino mass generation exists at the ay scale, we can anticipate new particle discovery at the LHC as well as large enhancement of lepton flavor violation processes. As an example of such a scenario, we study relationship between tau and muon lepton flavor violation processes and neutrino mass generation mechanism in the left-right symmetric model.3. little Higgs model and dark matterIt is pointed out that the recently proposed little Higgs model can accommodate a dark matter particle if the model is extended with the T-parity. We have studied phenomenological constraints and dark matter relic abundance in this model, and have investigated a possibility of detecting cosmic positron signals from the pair annihilation of dark matter particles in our galaxy under these constraints.