Symmetry breaking and effecto of heavy particles in electroweak gauge theories
Project/Area Number  04640298 
Research Category 
GrantinAid for Scientific Research (C).

Research Field 
核・宇宙線・素粒子

Research Institution  KYOTO UNIVERSITY 
Principal Investigator 
INAMI Takeo Kyoto Univ., Yukawa Inst.for Theor.Phys., Assoc.Prof., 基礎物理学研究所, 助教授 (20012487)

CoInvestigator(Kenkyūbuntansha) 
LIM C.S. Kobe Univ., Phys.Dept., Assoc.Prof., 理学部, 助教授 (80201870)

Project Fiscal Year 
1992 – 1993

Project Status 
Completed(Fiscal Year 1993)

Budget Amount *help 
¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1993 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1992 : ¥800,000 (Direct Cost : ¥800,000)

Keywords  Electroweak gauge theory / Symmetry Breaking / Heavy particle / Fermion generations / Radiative Corrections / 弱・電磁ゲージ理論 / 対称性の破れ / 重い粒子 / フェルミオンの世代 / 輻射補正 / 弱電磁ゲージ理論 
Research Abstract 
The gauge theory based on the group SU(3) X SU(2)_L X U(1) is in good accord (with some uncertainty) with various kinds of measurements in electroweak interactions. For this model to be established as the unified theory of strong and electroweak interactions, it is crucial to make precision testy of radiative corrections in this theory. The purposes of the present research project are the following : a) To study the physics law at energies E higher than the weakboson mass scale M_W, in particular, the effects of possible heavy particles through radiative corrections in light particle processes. b) Research aiming at understanding the nature of the Higgs particle. c) Phenomenological study to determine the properties of quarks and leptons. Regarding the purposes a) and c) we have studied the nondecoupling effects of heavy particles in the gauge boson two and threepoint couplings and have obtained a few interesting results (as summarized in the report "Precision Test of ElectroWeak Parameters and New Physics" ) : 1) The analysis of the symmetry properties of the S, T, U parameters of the twopoint functions is useful in understanding the oblique corrections. 2) Comparison with the precision measurements of S and T gives a meaningful upper bound on the number of extra generations N_<eg>. 3) Regarding the triple gaugeboson couplings, we have identified the four parameters which are sufficient to describe the nondecoupling effects of heavy particles in the gammaW^+W^ and Z^OW^+W_ couplings. As for the purpose b), we have studied the properties of the Higgs in theories in which it is given a geometrical role in extra dimensions of spacetime. The research in this direction is still in progress.

Report
(4results)
Research Output
(14results)