Phenomenologies of the hierarchy-problem solving models

Abstract

We study the phenomenologies of two hierarchy-problem solving models, the Minimal Supersymmetric Standard Model (MSSM) and the Randall-Sundrum model. In terms of the naturalness dogma in the sense of `t Hooft, the hierarchy problem is regarded as a problem that we should find a symmetry which makes the electroweak scale robustly much smaller than the Planck scale. We review the basic materials of supersymmetry (SUSY), e.g. the SUSY algebra, representations and multiplets, the spontaneous breaking mechanisms of SUSY, the supersymmetric renormalization, and the Minimal Supersymmetric Standard Model. In the MSSM, we consider the effects of the CP-violating phases, $arg(A_t)$ and $arg(μ)$, on the $e^+ e^- → {\tilde t}_1 {\tilde {t_1}}^* (H_1)$ processes. The CP-violating phase $arg(A_t)$ has significant effects on the associated Higgs production rather than the stop pair production. And we will discuss the determination method of soft parameters. We review the phenomenologically important things of the Randall-Sundrum (RS) model, e.g. the set-up and the solution of the hierarchy problem, the stabilization of the extra dimension, the mass and coupling of radion, and the Kaluza-Klein decompositions of bulk fields. Firstly, we consider the phenomenology of the radion φ at colliders, for example, the decay rates and branching ratios of the radion, the unitarity bounds on the coupling and mass, and the production cross sections at $e^+ e^-$ and hadron colliders. Secondly, in the context of the Goldberger-Wise mechanism, we find the one-loop lower and upper bounds of the radion mass $m_φ$ and the radion-Standard Model coupling constant $Λ_φ$ from the vacuum stability. It is phenomenologically important that the upper bound of the radion mass is about five times enhanced by one-loop effects than the tree-level one. Thirdly, we discuss the effective theory construction and the muon anomalous magnetic moment in the RS model.