Study of the Standard Model on the Lattice with Massively Parallel Computer CP-PACS

2005 Fiscal Year Final Research Report Summary

• 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)
• Project Period (FY): 2003 – 2005
• Keywords: lattice gauge theory / lattice quantum chromodynamics / numerical simulation / quarks and gluons / phase transition / strong interactions / Monte Carlo methods / perturbation theory

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 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.

Research Products

• [Journal Article] Nonperturbative 0(a) improvement of the Wilson quark actoon with the RG-improved gauge action using the Schrodinger functional method (2006)
  • Author(s): S.Aoki et al.
  • Journal Title: Physical Review D73 Pages: 034501
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Nonperturbative O(a) improvement of the Wilson quark action with the RG-improved gauge action using the Schr"odinger functional method (2006)
  • Author(s): CP-PACS and JLQCD Collaborations : S.Aoki, M.Fukugita, S.Hashimoto, K-I.Ishikawa, N.Ishizuka, Y Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramashi, M.Okawa, S.Takeda, Y.Taniguchi, N.Tsutsui, A.Ukawa, N.Yamada, T.Yoshie
  • Journal Title: Phys.Rev.D 73 Pages: 034501
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Non-perturbative 0(a)-improvement of Wilson quark action in three-flavor QCD with plaquette gauge action (2005)
  • Author(s): N.Yamada et al.
  • Journal Title: Physical Review D71 Pages: 054505
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] A scaling study of the step scaling function in SU(3) gauge theory with improved gauge actions (2005)
  • Author(s): S.Takeda et al.
  • Journal Title: Physical Review D70 Pages: 075401
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] I=2 Pion Scattering length from two-pion wave function (2005)
  • Author(s): S.Aoki et al.
  • Journal Title: Physical Review D71 Pages: 094504
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Neutron dipole moment from lattice QCD (2005)
  • Author(s): E.Shintani et al.
  • Journal Title: Physical Review D72 Pages: 014504
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Neutron electric dipole moment from lattice QCD (2005)
  • Author(s): E.Shintani, S.Aoki, N.Ishizuka, K.Kanaya, Y.Kikukawa, Y.Kuramashi, M.Okawa, Y.Tanigchi, A.Ukawa, T.Yoshie
  • Journal Title: Phys.Rev.D 72 Pages: 014504
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] I=2 Pion Scattering Length from Two-Pion Wave Functions (2005)
  • Author(s): CP-PACS Collaboration : S.Aoki, M.Fukugita, K-I.Ishikawa, N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramashi, M.Okawa, A.Ukawa, T.Yamazaki, T.Yoshie
  • Journal Title: Phys.Rev.D 71 Pages: 094504
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Non-perturbative O(a)-improvement of Wilson quark action in three-flavor QCD with plaquette gauge action (2005)
  • Author(s): CP-PACS and JLQCD Collaborations : N.Yamada, S.Aoki, M.Fukugita, S.Hashimoto, K-I.Ishikawa, N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramashi, M.Okawa, Y.Taniguchi, N.Tsutsui, A.Ukawa, T.Yoshie
  • Journal Title: Phys.Rev.D 71 Pages: 054505
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Non-perturbative calculation of Z_V and Z_A in domain-wall QCD on a finite box (2004)
  • Author(s): S.Aoki et al.
  • Journal Title: Physical Review D70 Pages: 034503
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] I=2 pipi Scattering Phase Shift with two Flavors of 0(a) Improved Dynamical Quarks (2004)
  • Author(s): T.Yamazaki et al.
  • Journal Title: Physical Review D70 Pages: 074513
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Lattice QCD calculation of the proton decay matrix element in the continuum limit (2004)
  • Author(s): N.Tsutsui et al.
  • Journal Title: Physical Review D70 Pages: 111501
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Light hadron spectroscopy in two-flavor QCD with small sea quark masses (2004)
  • Author(s): Y.Namekawa et al.
  • Journal Title: Physical Review D70 Pages: 074503
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Non-perturbative renormalization of meson decay constants in quenched QCD for a renormalization group improved gauge action (2004)
  • Author(s): K.Ide eta l
  • Journal Title: Physical Review D70 Pages: 074502
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] A scaling study of the step scaling function in SU(3) gauge theory with improved gauge actions (2004)
  • Author(s): CP-PACS Collaboration : S.Takeda, S.Aoki, M.Fukugita, K-I.Ishikawa, N.Ishizuka, Y.Iwasaki, K Kanaya, T.Kaneko, Y.Kuramashi, M.Okawa, Y.Taniguchi, A.Ukawa, T.Yoshie
  • Journal Title: Phys.Rev.D 70 Pages: 074510
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Non-perturbative renormalization of meson decay constants in quenched QCD for a renormalization group improved gauge action (2004)
  • Author(s): CP-PACS Collaboration : K.Ide, S.Aoki, R.Burkhalter, M.Fukugita, S.Hashimoto, K-I.Ishikawa, T.Ishikawa, N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramashi, V.Lesk, M.Okawa, Y.Taniguchi, T.Umeda, A.Ukawa, T.Yoshie
  • Journal Title: Phys.Rev.D 70 Pages: 074502
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Light hadron spectroscopy in two-flavor QCD with small sea quark masses (2004)
  • Author(s): CP-PACS Collaboration : Y.Namekawa, S.Aoki, M.Fukugita, K-I.Ishikawa, N.Ishizuka, Y.Iwasaki, K Kanaya, T.Kaneko, Y.Kuramashi, V.I.Lesk, M.Okawa, A.Ukawa, T.Umeda, T.Yoshie
  • Journal Title: Phys.Rev.D 70 Pages: 074503
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Lattice QCD calculation of the proton decay matrix element in the continuum limit (2004)
  • Author(s): CP-PACS and JLQCD Collaborations : N.Tsutsui, S.Aoki, M.Fukugita, S.Hashimoto, K-I.Ishikawa, N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramashi, M.Okawa, T.Onogi, Y.Taniguchi, A.Ukawa, T.Yoshie
  • Journal Title: Phys.Rev.D 70 Pages: 111501
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] I=2 pi-pi Scattering Phase Shift with two Flavors of O(a) Improved Dynamical Quarks (2004)
  • Author(s): CP-PACS Collaboration : T.Yamazaki, S.Aoki, M.Fukugita, K-I.Ishikawa, N.Ishizuka, Y.Iwasaki, K Kanaya, T.Kaneko, Y.Kuramashi, M.Okawa, A.Ukawa, T.Yoshie
  • Journal Title: Phys.Rev.D 70 Pages: 074513
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Non-perturbative calculation of Z_V and Z_A in domain-wall QCD on a finite box (2004)
  • Author(s): CP-PACS Collaboration : S.Aoki, M.Fukugita, N.Ishizuka, Y.Iwasaki, K.Kanaya, T.Kaneko, Y.Kuramashi, M.Okawa, Y.Taniguchi, A.Ukawa, T.Yoshie
  • Journal Title: Phys.Rev.D 70 Pages: 034503
  • Description: 「研究成果報告書概要(欧文)」より