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STUDY ON THE SPIN STRUCTURE OF NUCLEONS

Research Project

Project/Area Number 05044046
Research Category

Grant-in-Aid for international Scientific Research

Allocation TypeSingle-year Grants
SectionJoint Research
Research InstitutionNagoya University

Principal Investigator

HORIKAWA Naoaki  Nagoya University, Faculty of Science, Associate Professor, 理学部, 助教授 (70022697)

Co-Investigator(Kenkyū-buntansha) SAVIN I.  Joint Institute for Nuclear Research, Dubna, RUSSIA,Professor, JINR研究所, 教授
NIINIKOSKI Tapio  European organization for nuclear Research, Research Associate, 研究員
IGO G.J.  カリフォルニア大学, 物理学科, 教授
HUGHES V.W.  エール大学, 物理学科, 教授
SAWADA Shoji  Nagoya University, Faculty of Science, Professor, 理学部, 教授 (50022546)
YASUNO Masaru  Nagoya University, Faculty of Science, Professor, 理学部, 教授 (30022544)
ISHIMOTO Shigeru  National Laboratory for High Energy Physics, Research Associate, 助手 (50141974)
MATSUDA Tatsuro  Miyazaki University, Faculty of Engineering, Research Associate, 工学部, 助手 (20253817)
HASEGAWA Takeo  Miyazaki University, Faculty of Engineering, Professor, 工学部, 教授 (70025386)
MORI Kunikazu  Nagoya University, College of Medical Techmology, Professor, 医療技術短期大学部, 教授 (70022663)
IWATA Takahiro  Nagoya University, Faculty of Science, Research Associate, 理学部, 助手 (70211761)
IGO George  California University, Professor
HUGHES Vernon  Yale University, Professor
IGO G.  UCLA, 物理学科, 教授
TRENTALANGE エス.  UCLA, 物理学科, 助手
Project Period (FY) 1993 – 1994
Project Status Completed (Fiscal Year 1994)
Budget Amount *help
¥20,000,000 (Direct Cost: ¥20,000,000)
Fiscal Year 1994: ¥10,000,000 (Direct Cost: ¥10,000,000)
Fiscal Year 1993: ¥10,000,000 (Direct Cost: ¥10,000,000)
KeywordsSpin / Nucleon Spin / Quark Spin / Spin Polarized Target / Spin Polarized Muon Beam / Ellis-Jaffe Sum Rule / Bjorken Sum Rule / Spin Crisis / 偏極標的 / 偏極核子 / 核子構造
Research Abstract

SMC (Spin Muon Collaboration) is now going on the experiment using the high energy polarized muon and polarized proton/deutron targets. This experiment aims at making clear the origin of the nucleon spin and cheking the validity of the QCD which is used for the prediction of the quark-gluon behavior inside hadrons. SMC has performed two experiments in this term (2 years) at CERN.In 1993, the spin dependent structure function of the proton has been measured. In 1994, the same parameter of the deuteron was measured. The former experiment extended the data points to the lowest x region with higher statistics. The latter data are now under analysis.
The measurement of the spin-dependent structure function of proton has been achieved under the following conditions. (1) The polarized muon beam had an intensity of 4*10^7ppp with a polarization of 80%. (2) The polarized proton target has a dimension of 50mmphi* 650mmlong. A pair of this target capsuls are installed in a dilution cryostat with opposite direction of the polarization. The value of the polarization was about 45%. The data extended the x-region to 0.003 with fairly better statistical and systematic errors. Whole number of data was 4.4*10^6 events.
From the proton data, the following results are derived. (1) The Eliis-Jaffe sum rule which is calculated by the assumption of naive quark model is not valified by the experiment. There is about two standard deviation between the prediction and measurement. (2) The sum of the quark spins inside proton can bring only 22% and the strange quark spin has a contribution of -12%. This requires to look for the origin of nucleon spin. (3) The Bjorken sum rule which is a key relation to check the QCD was tested and guaranteed to be correct within errors.

Report

(2 results)
  • 1994 Final Research Report Summary
  • 1993 Annual Research Report
  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] N.Horikawa et al.: "Measurement of the Deuteron Polarization in a Large Target" Nucl.Instr.and Meth.A349. 334-344 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] N.Horikawa et al.: "Measurement of the Spin-Dependent Structure Function g_1(x) of the Proton" Phys.Lett.B329. 399-406 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] N.Horikawa et al.: "Spin Asymmetry in Muon-Proton Deep Inelastic Scattering on a Transversely Polarized Target" Phys.Lett.B336. 125-130 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] N.Horikawa et al.: "The Present Status of the Nucleon Spin Structure Functions" Nucl.Phys.A577. 313C-318C (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 堀川直顕: "核子スピンの起源をめぐる新しい実験とその展開" 日本物理学会誌. Vol.49. 913-916 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] N.Horikawa, et al.: "Measurement of the Deuteron Polarizationin a Large Target." Nucl.Instr.and Meth.A349. 334-344 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] N.Horikawa, et al.: "Measurement of the Spin-Dependent Structure Function g_1(x) of the Proton." Phys.Lett.B329. 399-406 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] N.Horikawa, et al.: "Spin Asymmetry in Muon-Proton Deep Inelastic Scattering on a Transversely Polarized Target." Phys.Lett.B336. 125-130 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] N.Horikawa: "The Present Status of the Nucleon Spin Structure Functions." Nucl.Phys.A577. 313-318 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] N.Horikawa: "The new Experiment and Development on the Origin of the Nucleon Spin.(in Japanese)" "BUTSURI". Vol.49. 913-916 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] B.Adeva et al.(SMCメンバー): "Measurement of the spin-dependent structure function g_1(x) of the deuteron" Phys.Letters.B. 302. 533-539 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] B.Adeva et al.(SMCメンバー): "Combined analysis of world data on nucleon spin structure functions" Phys.Letters B. 320. 400-406 (1994)

    • Related Report
      1993 Annual Research Report
  • [Publications] B.Adeva et al.(SMCメンバー): "Measurement of the polarization of a high energy muon beam" Nucl.Instr.and Meth.(submitted).

    • Related Report
      1993 Annual Research Report
  • [Publications] B.Adeva et al.(SMCメンバー): "Measurement of the deuteron polarization in a large target" Nucl.Instr.and Meth.(submitted).

    • Related Report
      1993 Annual Research Report
  • [Publications] 岸淳,堀川直顕,岩田高広,中須賀徳行: "周波数シンセサイザーを使った偏極度測定と標的の開発" 原子核研究. 38. 1-26 (1994)

    • Related Report
      1993 Annual Research Report

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Published: 1993-04-01   Modified: 2016-04-21  

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