Higgs Particle Hunting and Attempts going beyond the Standard Model

在考虑辐射修正的双希格斯双重态模型中，计算了希格斯玻色子到规范玻色子对的衰减率。我们发现，通过辐射修正的重未知粒子的效应总是亚光的。这是筛选定理的推广。在双希格斯双重态模型中计算了规范玻色子弹性散射的单圈修正，在最小超引力模型和多希格斯双重态模型中计算了b→sl^+L^-，b→Svv^^-等底夸克的衰变过程。在超引力模型中发现衰变b→sl^+L^-的分支比可能比标准模型中的大得多。为了在加速器实验中获得轻子味破坏的信号，我们研究了μ^+μ^-(e^+e^-)→τμ+4jets+缺失能量和μ^+μ^-(e^+e^-)→τμL+2jets+缺失能量过程。为了探索标准模型之外的理论，我们冒险研究了量子场论和超弦的各个方面。更具体地说，我们研究了在Seiberg-Witten理论的模空间中特定点实现的超共形不变性。我们还根据Chern-Simons理论推导了三维反de Sitter引力的渐近共形不变性，并用共形场论方法推导了黑洞的熵。对于超弦的研究，我们的研究包括从M理论的角度研究N=2 QCD，D5膜的二次量子化，Hanany-Witten效应及其与D2膜电荷决定的关系。

The decay rates of Higgs boson into gauge boson pairs were evaluated in the two-Higgs doublet model including radiative corrections. We have found that the effects of heavy unknown particles through radiative corrections are always subleading. This is a generalization of the screening thorem. One-loop corections to the elastic scattering of gauge bosons have also been evaluated in the two-Higgs doublet model.The decay processes of the bottom quark such as b→sl^+l^-, b→svv^^- have been calculated in the minimal supergravity model and multi-Higgs doublet model. It was found in the supergravity model that the branching ratio of the decay b→sl^+l^- could be much larger than in the standard model.To get signals of lepton-flavor violation in accelerator experiments, we have investigated the processes μ^+μ^- (e^+e^-)→τμ+4jets+missing-energy, and μ^+μ^- (e^+e^-)→τμl+2jets+missing energyTo probe the theory beyond the standard model, we have ventured to study various aspects of quantum field theories and superstring. More concretely, we have investigated superconformal invariance realized in particular points in the moduli space of the Seiberg-Witten theory. We have also worked out the derivation of the asymptotic conformal invariance of the three-dimensional anti-de Sitter gravity based on the Chern-Simons theory, and the black hole entropy in the conformal field theory approach. As to the study of superstring, our research includes the investigation of the N=2 QCD from the viewpoints of M-theory, second quantization of the D5-brane, and the Hanany-Witten effects and its relation to the determination of the charge of D2-brane.