2006 Fiscal Year Final Research Report Summary
Research on the coupling constant and its scale dependence via lattice QCD simulations
| 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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| Keywords | lattice QCD / numerical simulations / scale dependence of the coupling constant / Schrodinger functional / chiral perturbation theory |
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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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[Book] 格子上の場の理論2005
Author(s)
青木 慎也
Total Pages
321
Publisher
シュプリンガー・フェアラーク東京
Description
「研究成果報告書概要(和文)」より
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