Determination of the direct CP violation parameter in the K meson decay by the lattice QCD

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H03650
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: University of Tsukuba
• Principal Investigator: ISHIZUKA Naruhito 筑波大学, 計算科学研究センター, 准教授 (70251030)
• Co-Investigator(Kenkyū-buntansha): 宇川 彰 国立研究開発法人理化学研究所, 計算科学研究機構, 副機構長 (10143538) ; 吉江 友照 筑波大学, 計算科学研究センター, 准教授 (40183991)
• Co-Investigator(Renkei-kenkyūsha): ISHIKAWA Kennichi 広島大学, 理学研究科, 准教授 (60334041)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: CP非保存パラメータ / K中間子崩壊振幅 / 格子場の理論

Outline of Final Research Achievements

An aim of this project is a study of the direct CP violation parameter from the Standard model of the particle physics by lattice calculation of the neutral K meson decay amplitudes. We consider the physical K meson decay process to the two pion with the finite momentum. In order to realize this on the lattice, our numerical calculations are carried out on heavier quark mass than the real world, the pion mass 250 MeV. Our result is Re(ε'/ε)=(1.6±5.6)e-3. This in consistent with the experimental value : (1.66±0.23)e-3, but the statistical error should be reduced by 1/20 for a precise comparison. This is an important problem reserved for the future.

Free Research Field

素粒子物理学