Search for Physics Beyond the Standard Model from the Higgs Precision Measurements

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K05047
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Nagoya University
• Principal Investigator: Tanabashi Masaharu 名古屋大学, 理学研究科, 教授 (00270398)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 電弱対称性の破れ / 低エネルギー有効理論 / 素粒子現象 / ヒッグス

Outline of Final Research Achievements

We investigate W′ interpretations for the ATLAS 2 TeV diboson anomalies. We find the unitarity sum rules and the custodial symmetry are powerful enough to predict various nontrivial relations among WWZ′, WZW′, WWh, WW′h and ZZ′h coupling strengths in a model independent manner.
A generalization of Higgs effective field theory (HEFT) including arbitrary number of extra neutral and charged Higgs bosons (generalized HEFT, GHEFT) is formulated to describe non-minimal electroweak symmetry breaking models. It is shown that the scalar boson scattering amplitudes are described in terms of the Riemann curvature tensor (geometry) of the scalar manifold and the covariant derivatives of the potential.
We also prposed a novel possibility of the DM model buildings in which the mediator particle m is unified with the DM particle d in an approximate dark symmetry multiplet. A pionic DM model is proposed to illustrate this idea in a renormalizable field theory framework.

Free Research Field

素粒子理論

Academic Significance and Societal Importance of the Research Achievements

2012年にLHC実験で発見されたヒッグス粒子は、素粒子標準理論の予言する唯一のスカラー素粒子であり、あらゆる素粒子の質量の起源を担うと考えられている。しかしながら、素粒子標準理論にはヒッグス粒子以外のスカラー素粒子は存在せず、ヒッグス粒子の正体は、いまだ謎に包まれている。本研究は、ユニタリティーやくりこみ可能性といった純理論的な制約が、ヒッグス粒子あるいはその拡張模型の性質にどのような制限を与えるかを明らかにするものである。今後、ヒッグス粒子結合の精密測定が進むことで、素粒子標準模型の破綻が明らかになることが期待される。