Nucleon structure in domain-wall-fermion lattice QCD

2019 Fiscal Year Final Research Report

• Project/Area Number: 15K05064
• 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: High Energy Accelerator Research Organization
• Principal Investigator: Ohta Shigemi 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 准教授 (50183025)
• Project Period (FY): 2015-10-21 – 2020-03-31
• Keywords: 場の量子論 / 格子上の場の量子論 / ハドロン物理学 / 素粒子現象論 / 数値物理学 / スーパーコンピューター

Outline of Final Research Achievements

Nucleon structure calculations using three 2+1-flavor domain-wall fermion lattice QCD ensembles with a lattice cutoff momentum of about 1.38GeV/c and pion mass of about 249 and 172 MeV and another cutoff momentum of about 1.73GeV/c and pion mass of almost physical 139MeV were advanced. In the former two ensembles the calculations of nucleon mass, isovector vector and axialvector charges, and isovector tensor and scalar couplings were completed and a full paper reporting these were published. Calculations of the same observables in the last ensemble progressed: for the first time in the world an influence from nucleon excited state was confirmed in the isovector vector charge. Also the calculated value of the isovector axialvector charge slightly undershoots the experimental value.

Free Research Field

素粒子物理学

Academic Significance and Societal Importance of the Research Achievements

核子は我々人類やその生存環境を形作る様々な元素の基本構成要素で、その質量やアイソベクトル極性・軸性荷電はその存在量や構成比を決定する物理量なので、これらについての理論的理解を深めることは我々の存在の宇宙論的進化の歴史を理解し、将来を予測するのに役立つ。またアイソベクトルテンソル・スカラー両結合の値は素粒子の標準模型を超える新物理学の探索に役立つ。