Exploration of physics beyond the standard model through flavor physics

1.超对称模型中风味物理的研究超对称性被认为是在TeV尺度上很有前途的新物理候选者，寻找超对称粒子是LHC实验的主要目标。如果在那里发现超对称粒子，味道物理将在肠道和/或拉锯中微子尺度的探测理论中发挥重要作用。我们计算了几个超对称模型在B衰变、K衰变和轻子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T介子衰变和半T介子衰变的分支比，并证明了这些量的测量与LHC.2带电Higgs玻色子搜索的协同性。左右对称模型中的轻子味破坏中微子的小质量为超越标准模型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尺度上，我们可以预见在大型强子对撞机上发现新的粒子以及轻子味道破坏过程的大幅增强。作为这种情形的一个例子，我们研究了左右对称模型中的tau和muon轻子味破坏过程之间的关系以及中微子质量的产生机制。小Higgs模型与暗物质指出，最近提出的小Higgs模型如果用T宇称来扩展，它可以容纳暗物质粒子。我们研究了这个模型中的唯象约束和暗物质遗迹丰度，并研究了在这些约束下探测我们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.