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2002 Fiscal Year Final Research Report Summary

Study of Nucleon Spin Structure Functions based on an Effective Model of QCD

Research Project

Project/Area Number 12640267
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 素粒子・核・宇宙線
Research InstitutionOsaka University

Principal Investigator

WAKAMATSU Masashi  Osaka Univ., Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (40135653)

Co-Investigator(Kenkyū-buntansha) KUBOTA Takahiro  Osaka Univ., Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (80161678)
Project Period (FY) 2000 – 2002
Keywordsnucleon spin structure functions / nucleon spin puzzle / effective model of QCD / chiral symmetry / chiral soliton / deep-inelastic scattering / sea-quark distributions / nonperturbative QCD
Research Abstract

We have completed the theoretical calculation of the unpolarized and longitudinally polarized twist-2 parton distribution functions within the framework of the chiral quark soliton model. It was shown, that, without any adjustable parameter except for the initial-energy scale of the Q^2-evolution, the model can explain all the qualitatively noticeable features of the recent high-energy deep-inelastic Scattering observables. They include the NMC data for F^p_2(x) - F^n_2 (x), F^n_2(x)/F^p_2(x), the HERMES and E866 data for d^^-(x) - u^^-(x) data, and the EMC and SMC data for g^p_1(x), g^n_1(x) and g^d_1(x). We have also given theoretical predictions for the light-flavor sea-quark distributions in the nucleon including the strange quark one by extending the model to flavor SU(3). A particular emphasis of study is put on the light-flavor sea-quark asymmetry as exemplified by the observables d^^-(x) - u^^-(x), d^^-(x)/u^^-(x), Δu^^-(x) - Δd^^-(x) as well as on the particle-antiparticle asy … More mmetry of the strange quark distributions represented by s(x) - s^^-(x), s(x)/s^^-(x), Δs(x) - Δs^^-(x) etc. We also investigated the spin-dependent structure function g_2(x, Q^2). It turns out that the twist-3 part of g_2(x, Q^2) gives nonnegligible contributions to the total distributions at the energy scale of Q^2 - 5 GeV^2 but mainly in the small x region only, so that the corresponding third moment ∫^1_0 x^2 g^^-_2(x, Q^2) dx are pretty small for botb of the proton and neutron in conformity with the recent E155 data. Also given are the predictions for the twist-2 and twist-3 chirally-odd distribution functions of the nucleon. The importance of the vacuum polarization effects, which are properly taken into account within the framework of the chiral quark soliton model, is demonstrated by showing that the so-called Soffer inequality holds not only for the quark distributions but also for the antiquark ones. We have also succeeded in proving that the nonvanishing quark condensate as a signal of the spontaneous chiral symmetry breaking of the QCD vacuum brings about a delta-function singularity at x = 0 in the chirally-odd twist-3 distribution functions e (x) of the nucleon. This singularity in e (x), which would be observed as a sizable violation of the 1st moment sum rule, is then be interpreted as giving a very rare case that the nontrivial vacuum structure of QCD manifests in an obsrvable of a localized QCD excitation, i.e. the nucleon. Less

  • Research Products

    (46 results)

All Other

All Publications (46 results)

  • [Publications] 若松正志: "The nonporturbative origin of delta-function singularity in the chirally-odd twist-3 distribution function e(x)"Physical Review D. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Light-flavor sea-quark distributions in the nucleor in the SU(3) chirol quark soliton model (I)"Physical Review D. 67. 034005-1-034005-15 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Light-flavor sea-quark distributions in the nucleor in the SU(3) chirol quark soliton model (II)"Physical Review D. 67. 034006-1-034006-25 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Particle-antiparticle asymmetry of the nucleor strange sea"Proceedings of XVI Particle and Nucle : International Conference (PANIC2002). (印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Particle-antiparticle asymmetry of the nucleor strange sea"Proceedings of the 15th International Spin Physics Symposium(SPIN2002). (印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "A chiral theory of light flavor sea quark distributions in the nucleor"Progress of Theoretical Physics. 107. 1037-1045 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Quark-antiquark asymmetry of the Nucleor Strange Sea"Proceedings of the 3rd Circum-Par-Pacific Symposium on High Energy Spin Physics. (印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Chiral-odd distribution functions in the chiral quark soliton model"Physics Letters B. 509. 59-68 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Spin structure functions in the chiral quark soliton model"Proceedings of RIKEN BNL Research Center Workshop. 35. 163-206 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "核子スピンの謎をカイラル・クウォーク・ソリトン模型で解く"日本物理学会誌「最近の研究から」. 55. 705-709 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Solving the nucleor spin puzzle based on the chiral quark soliton model"Proceedings of the 14th International Spin Physics Symposium, AIP Conference Proceedings. 570. 482-486 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Polarized structure function g_2(x) in the chiral quark soliton model"Physics Letters B. 487. 118-124 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Spin and orbital angular momentum distribution functions of the nucleor"Physical Review D. 62. 054009-1-054009-7 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Chiral symmetry and the nucleor spin structure functions"Proceedings of the XIV International Seminar on High Energy Physics Problems, JINR rep.. 15-22 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Do we expect light flavor sea-quark asymmetry also for the spin-dependent distribution functions of the nucleor"Physical Review D. 62. 017506-1-017506-4 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 久保田高徳: "On the chiral quark soliton model with Douli-Villars regularization"Physical Review D. 60. 014016-1-014016-12 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Chiral symmetry and the nucleor spin structure functions"Physical Review D. 60. 034020-1-034020-33 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 若松正志: "Chiral symmetry and the nucleor structure functions"Physical Review D. 57. 5755-5766 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 窪田高弘: "The 1/N^2 correction to boundary Weyl anamaly in holographic renormalization"Journal of High Energy Physics. (印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 窪田高弘: "Maximally symmetric D-branes in gauged WZW models"Physics Letters B. 544. 182-198 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 江本大輝: "Cosmology in the Einstein-electroweak theory and magnetic fields"Progress of Theoretical Physics. 108. 157-183 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 窪田高弘: "RR charges of D2-branes in group manifold and Hanany-Witten effect"Journal of High Energy Physics. 12. 030-1-030-11 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 窪田高弘: "相対性理論"裳華房. 198 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M. Wakamatsu: "The nonperturbative origin of delta function singularity in the chirally-odd twist-3 distribution function e(x)^n"Physical Review D. in print. (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Light-flavor sea-quark distributions in the nucleon in the SU(3) chiral quark soliton model (I)"Physical Review. D67. 034005/1-15 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Light-flavor sea-quark distributions in the nucleonin the SU(3) chiral quark soliton model (II)"Physical Review. D67. 034006/1-25 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Particle-antiparticle asymmetry of the nucleon strange sea"in Proc. of PANIC2002. in print. (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Particle-antiparticle asymmetry of the nucleon strange sea"in Proc. of SPIN2002. in print. (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "A chiral theory of light flavor sea quark distributuions in the nucleon"Prog. Theor. Phys.. 107. 1037-1045 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Quark-antiquark asymmetry of the nucleon strange sea"in Proc. of High Energy Spin Physics. in press. (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Chiral-odd distribution functions in the chiral quark soliton model"Phys. Lett.. B509. 59-68 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Spin structure functions in the chiral quark soliton model"RIKEN Winter School. 35. 163-206 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Solving the nucleon spin puzzle based on the chiral quark soliton model"Butsuri. 55. 705-709 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Solving the nucleon spin puzzle based on the chiral quark soliton model"AlP Conference Proc.. 570. 482-486 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Polarized structure function g_2(x) in the chiral quark soliton moder"Phys. Lett.. B487. 118-124 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Spin and orbital angular momentum distribution functions of the nucleon"Phys. Rev.. D62. 054009/1-7 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Chiral symmetry and the nucleon spin structure functions"JINR conference report. 15-22 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Do we expect light flavor sea-quark asymmetry also for the spin-dependent distribution functions of the nucleon"Phys. Rev.. D62. 017506/1-4 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T. Kubota: "On the chiral quark soliton model with Pauli-Villars regularization"Phys. Rev.. D60. 014016/1-12 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Chiral symmetry and the nucleon spin structure functions"Phys. Rev.. D60. 034020/1-33 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Wakamatsu: "Chiral symmetry and nucleon structure functions"Phys. Rev.. D57. 5755-5766 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] "The 1/N^2 correction to boundary Weyl anomaly in holographic renormalization"Journal of High Energy Physics. in press. (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T. Kubota: "Maximally symmetric D-brane in gauged WZW models"Phys. Lett.. B544. 182-198 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H. Emoto: "Cosmology in the Einstein-electoweak theory and magnetic fields"Prog. Theor. Phys.. 108. 157-183 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T. Kubota: "RRcharges of D2brane in group manifold and Hanany-Witten effect"Journal of HEP. 12. 030/1-11 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T. Kubota: "Theory of Relativity"Syokabo. (2001)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2004-04-14  

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