| Project/Area Number |
15204015
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
|
|---|
| Research Institution | University of Tsukuba |
|---|
Principal Investigator |
UKAWA Akira University of Tsukuba, Graduate School of Natural and Applied Sciences, Professor, 大学院・数理物質科学研究科, 教授 (10143538)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
IWASAKI Yoichi University of Tsukuba, President, 学長 (50027348)
AOKI Sinya University of Tsukuba, Graduate School of Natural and Applied Sciences, Professor, 大学院・数理物質科学研究科, 教授 (30192454)
KANAYA Kazuyuki University of Tsukuba, Graduate School of Natural and Applied Sciences, Professor, 大学院・数理物質科学研究科, 教授 (80214443)
YOSHIE Tomoteru University of Tsukuba, Graduate School of Natural and Applied Sciences, Associate Professor, 大学院・数理物質科学研究科, 助教授 (40183991)
ISHIZUKA Naruhito University of Tsukuba, Graduate School of Natural and Applied Sciences, Associate Professor, 大学院・数理物質科学研究科, 助教授 (70251030)
石川 智己 筑波大学, 計算科学研究センター, 研究員 (70375377)
|
|---|
| Project Period (FY) |
2003 – 2005
|
| Project Status |
Completed (Fiscal Year 2005)
|
| Budget Amount *help |
¥47,450,000 (Direct Cost: ¥36,500,000、Indirect Cost: ¥10,950,000)
Fiscal Year 2005: ¥13,650,000 (Direct Cost: ¥10,500,000、Indirect Cost: ¥3,150,000)
Fiscal Year 2004: ¥13,390,000 (Direct Cost: ¥10,300,000、Indirect Cost: ¥3,090,000)
Fiscal Year 2003: ¥20,410,000 (Direct Cost: ¥15,700,000、Indirect Cost: ¥4,710,000)
|
|---|
| Keywords | lattice gauge theory / lattice quantum chromodynamics / numerical simulation / quarks and gluons / phase transition / strong interactions / Monte Carlo methods / perturbation theory / 格子QCD / クォーク / クローバー作用 |
|---|
| Research Abstract |
This project carried out an extensive Nf=2+1 lattice QCD simulation including dynamical effects of all three light quarks, u, d, s using the fully O(a) improved Wilson-clover quark action and RG-improved gluon action at three lattice spacings a=0.071fm, 0.1fm and 0.12fm. Detailed study was made of the light hadron spectrum, light quark masses and heavy quark physics, taking a systematic continuum extrapolation. The main results are as follows :
(1) Light hadron spectrum
In quenched QCD a systematic deviation of up to 10% is known to exist in the meson and baryon spectrum. The present calculation has shown that this deviation goes away in the Nf=2+1 calculations, the results showing an agreement with experiment at a 1% level. Systematic errors, however, arising from the fact that quarks are still relatively heavy in the simulations need to be assessed using Wilson chiral perturbation theory. Preliminary analyses show that they are consistent with polynomial extrapolation.
(2) Light quark m
… More
asses
The meson spectrum results allow us to evaluate the light quark masses, for which we find in the continuum limit, m=3.49(15)MeV for the average of u and d quark mass in the MS scheme at μ=2GeV, and m=90.9(3.7)MeV for s quark. These values are about 2/3 of the phenomenologically widely used values.
(3) Heavy quark physics
Extensive tests were made of the relativistic heavy quark action proposed by the members of the project. Test calculations in quenched QCD for the bottomonium spectrum and B meson decay constants with a non-perturbative tuning of speed of light showed excellent scaling behavior. Encouraged by the success, calculations on the dynamical Nf=2+1 flavor configurations are being made.
(4) Future perspective
The results obtained in this project have been presented at Lattice Symposia and various international conferences. A limitation encountered in the present calculation is difficulty of penetrating into the light quark mass region. Application of the domain-decomposed HMC algorithm recently proposed has been tested, and encouraging results were obtained for their use on the next generation PACS-CS computer. Less
|
