Manifestation of instanton effects

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K13487
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Hiroshima University
• Principal Investigator: Homma Kensuke 広島大学, 理学研究科, 助教 (40304399)
• Co-Investigator(Renkei-kenkyūsha): Sakabe Shuji 京都大学, 化学研究所, 教授 (50153903)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 強い相互作用

Outline of Final Research Achievements

The theta vacuum is known as a state of a degenerate vacuum characterized by its topological nature, the winding number, due to periodic boundary conditions. Instanton is understood as a tunneling transition in between different winding numbers. The theta vacuum is theoretically necessary to resolve the U(1) problem of QCD and also to interpret the CP invariance of the QCD Lagrangian by introducing a hypothetical particle, axion. However, the concept of the theta vacuum is still metaphysical and its physical existence has not been manifestly demonstrated to date. Therefore, we tried to phenomenologically actualize the essence of instanton in the laboratory experiment.

Free Research Field

素粒子原子核実験