Study of supersymmetric unified theory based on superstring theory
Project/Area Number  08640362 
Research Category 
GrantinAid for Scientific Research (C)

Section  一般 
Research Field 
素粒子・核・宇宙線

Research Institution  Kanazawa University 
Principal Investigator 
SUEMATSU Daijiro Kanazawa University, Department of Physics, Associate Professor, 理学部, 助教授 (90206384)

Project Fiscal Year 
1996 – 1997

Project Status 
Completed(Fiscal Year 1997)

Budget Amount *help 
¥1,700,000 (Direct Cost : ¥1,700,000)
Fiscal Year 1997 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1996 : ¥1,000,000 (Direct Cost : ¥1,000,000)

Keywords  Superstring / Supersymmetry / Unified theory / 超弦理論 / 超対称性 / 統一理論 
Research Abstract 
Phenomenological features of effective supersymmetric models derived as the low energy effective theory of superstring have been studied from various points of view. Main results obtained in this project are followings. 1. Models with an extra U (1) symmetry and a gauge singlet field can solve a muproblem in the minimal supersymmetric standard model (MSSM). In this kind of models a neutralino sector is extended by an extra U (1) gaugino and a fermion partner of the singlet scalar. There can appear typical examples are decays of neutralinos, an electric dipole moment of an electron and mu*egamma. We have analyzed these processes taking account of a kinetic term mixing of U (1) gauginos and shown that there could be substantial differences from the MSSM results. 2. We can realize small neutrino masses under a suitable condition in the models with an extra U (1). In this type of models group theoretical constraints on Yukawa couplings are not so strong and then a neutrino mass matrix can h
… More
ave a largely different structure from the one of usual grand unified models. Under assumptions of the existence of three righthanded neutrinos and mixings between a very heavy righthanded neutrino and other light neutrinos, we have constructed a phenomenological neutrino mass matrix. We have shown that in this model both deficits of solar and atmospheric neutrinos and the dark matter problem could be explained. We have also analyzed the relation of this model to the primordial nucleosynthesis and other neutrino oscillation experiments. 3. In order to know whether the models with an extra U (1) can solve the muproblem or not, we need to analyze the existence of the parameter region which satisfys both constraints from prescise measurements of the electroweak interaction and the radiative symmetry breaking at the electroweak scale. We have studied this subject taking account of an effect of the kinetic term mixing among U (1) gauge fields and shown that we could find such an parameter region. Less

Report
(4results)
Research Output
(20results)