| Project/Area Number |
15540251
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | University of Tsukuba |
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Principal Investigator |
AOKI Sinya University of Tsukuba, Graduate School of Pure and Applied Sciences, Professor, 大学院数理物質科学研究科, 教授 (30192454)
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| Project Period (FY) |
2003 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2005: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2004: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | lattice QCD / numerical simulations / scale dependence of the coupling constant / Schrodinger functional / chiral perturbation theory / ゲージ結合定数 / 改良されたゲージ作用 / シュレディンガー汎関数法 / 有理関数近似 / ツイストされたQCD / 非摂動的作用の改良 / 中性子電気双極子能率 / 格子 / モンテカルロ法 / 力学的クォーク / 弦の張力 / 摂動展開 / 境界改良係数 |
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| Research Abstract |
A purpose of this project is to calculate a scale dependence of the coupling constant, which is one of fundamental parameters in QCD, by lattice QCD simulations. We use a RG improved gauge action for gluons and a non-perturbatively improved Wilson fermion act ion for quarks. A step scaling function of the coupling constant is calculated by the Schrodinger functional method to evaluate the scale dependence of the coupling constant. As a first step, an improvement coefficient for a boundary term is determined at 1 loop in perturbation theory for a case of the RG gauge act ion. This determination of the coefficient is tested in quenched QCD simulations. We then have determined the clover coefficient for an improved term in the fermion action non-perturbatively in the Schrodinger functional setup. In addition, renormalization constants as well as improved coefficients for various operators are estimated by the Schrodinger functional method. On the other hand, we have calculated hadron spectra in 2+1 flavor full QCD simulations, in order to determine a low energy scale. A new theoretical method, called Wilson chiral perturbation theory, is proposed to control chiral extrapolations for Wilson type quarks and quark mass dependences for various quantities are calculated by this method. We have tested a new algorithm for light dynamical quarks, called domain-decomposed HMC algorithm, towards lattice QCD simulations at physical quark mass. An evaluation of SSF in 3 flavor QCD and a calculation of hadron spectra in 2+1 flavor QCD are now under way.
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