Lattice Numerical simulation of strong gauge dynamics for beyond the standard model

2015 Fiscal Year Final Research Report

• Project/Area Number: 25800139
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Institute of Physical and Chemical Research (2015); Nagoya University (2013-2014)
• Principal Investigator: Hiroshi Ohki 国立研究開発法人理化学研究所, 仁科加速器研究センター, 基礎科学特別研究員 (50596939)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 素粒子論 / 格子ゲージ理論

Outline of Final Research Achievements

Non-perturbative nature of many-flavor QCD through the numerical simulation of the lattice gauge theory within the framework of the (walking) technicolor model has been investigated. Many-flavor QCD is a good candidate for the walking technicolor, where the flavor singlet scalar can be regarded as a technidilaton, a pseudo Nambu-Goldstone boson of the approximate scale symmetry.
In this work, we studied the flavor dependence of the low-energy behavior systematically in comparison with various number of flavor Nf=(0), 8, 12 based on a unique lattice setup. We discovered a signal of a flavor-singlet scalar meson lighter than the pseudo scalar in Nf =12 case. In Nf =8 case, we also observed a flavor-singlet scalar with mass comparable to or slightly smaller than that of the pseudo scalar in the fermion mass range of our simulations. This is a hint of the technidilaton as a composite Higgs to be identified with the Higgs boson which was discovered at LHC.

Free Research Field

素粒子論