Investigating topology of QCD with domain-wall fermion action

2021 Fiscal Year Final Research Report

• Project/Area Number: 18H01216
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 15010:Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics
• Research Institution: Osaka University
• Principal Investigator: Fukaya Hidenori 大阪大学, 理学研究科, 助教 (70435676)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 格子ゲージ理論 / トポロジー / 量子色力学

Outline of Final Research Achievements

Simulating finite temperature lattice QCD at temperatures higher than 165MeV, we have found a strong suppression of the topological excitation or the effect of the axial U(1) anomaly. We computed the axial U(1) susceptibility as well as meson/baryon two point correlation functions and found a good consistency with the disappearance of the axial U(1) anomaly in the chiral limit. This results were published in Physical Review D and we recieved the HPCI Excellent Achievement Award in 2020. Also, we achieved a clean separation of the chiral susceptibility into the axial U(1) breaking contributions from others and found the effect of the anomaly dominates the signal by 90%.

Free Research Field

素粒子論

Academic Significance and Societal Importance of the Research Achievements

これまでの格子QCDシミュレーション、特に有限温度QCDシミュレーションでは、計算コストの問題があるために格子上でカイラル対称性を壊す理論定式化が使われてきた。この手法では、自発的カイラル対称性の破れが不明確になるばかりでなく、カイラル対称性と密接に関係する、ゲージ場のトポロジカルな性質も損なわれる。私たちの研究成果は、精密なカイラル対称性をもつ格子QCDシミュレーションで行われた世界初の試みであり、宇宙初期に起こったQCD相転移に対するトポロジカルな励起の効果を定量的に見積もることに成功した。