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1999 Fiscal Year Final Research Report Summary

Study of Spin Structure of the Proton and Nectron with Hadror Coincidence Method

Research Project

Project/Area Number 09304030
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field 素粒子・核・宇宙線
Research InstitutionTOKYO INSTITUTE OF TECHNOLOGY

Principal Investigator

SHIBATA Toshi-aki  Tokyo Institute of Technology Dept.Physics, Professor, 理学部, 教授 (80251601)

Co-Investigator(Kenkyū-buntansha) SAKEMI Yasuhiro  Tokyo Institute of Technology Dept.Physics, Research Assistant, 理学部, 助手 (90251602)
Project Period (FY) 1997 – 1999
Keywordsproton / neutron / quark / scattering / electron / polarization / gluon / spin
Research Abstract

In this project we have done 1) the experimental data analysis and 2) detector development at Tokyo Institute of Technology. The thema oa the project was the study of the quark-gluon structure of the spin of proton and neutron. The spin of the nucleon is 1/2. It was found by EMC in 1988 that only a small part of the nucleon spin is carried by quarks. We are participating in HERMES experiment at DESY in Hamburg in Germany. At HERMES the high energy polarized electron beam is scattered off the polarized nucleon target. The experimental data are sent from HERMES to our university. This experiment is a deep inelastic scattering. We mea sured not only the scattered electron but also produced hadrons (mesons, nucleons, lambda etc.) in coincidence. For that purpose we developped a Ring Imag ing CHerenkov counter (RICH) and installed into HERMES.Pions, kaons, protons and anti-protons at 2-20Gev/c are identified with the RICH.Polarized u, d, and s quark distributions in the nucleon are determined.
Furthremore, transversity of the quark spin was studied for the first time. This is a study of the distribution of the quark whose spin is perpendicular to the nucleon spin. At HERMES the angle between the electron scattering plane and the pion production direction was measured by reversing the target nucleon spin direction. We succeeded to observe a non-zero asymmetry. 'Transversity' of the quark spin is a new field and will attract many physicists in the near future to study it further.

  • Research Products

    (21 results)

All Other

All Publications (21 results)

  • [Publications] T.-A.Shibata et al.: "A high precision laser alignment monitoring system for fracking detectors of HERMES"Nucl.Instrum.Methods. A411. 75-80 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] A.Airapetian et al.: "Measurement of the proton spin structure function g^P_1 with a pure hydrogentarget"Phys.Lett.. B442. 482-492 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Ackerstaff et al.,: "Flavour asymmetry of the light quark sea from semi-inclusive deep inelastic scattering"Phys.Rev.Lett.. 81. 5519-5* (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Ackerstaff et al.: "Flavor decomposition of the polarized quark distributions in the nucleon from inclusive and semi-Inclusive deep inelastic scattering"Phys.Lett.. B464. 123-124 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] A.Airapetian et al.: "Measurement of the spin asymmetry in the photo-production of pairs of high Pt hadrons at HERMES"Phys.Rev.Lett.. 84. 2584-2588 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] A.Airapetian et al.: "Evidence for a single-spin azimuthal asymmetry in semi-inclusive pion electroproduction"Phys.Rev.Lett.. 84. 4047-4051 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Ackerstaff et al.: "Measurements of the neutron spin structure function g^n_1 with a polarized ^3He target"Phys.Lett.. B404. 383-389 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.-A.Shibata, Y.Sakemi, H.Kobayashi, S.Yoneyama, T.Harano, K.Shibatani, M.Kurisuno, H.Ogami, and C.A.Miller: "A high precision laser alignment monitoring system for tracking detectors of HERMES"Nucl.Instrum.Meths.. A411. 75-80 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ackerstaff et al.: "The HERMES spectrometer"Nucl.Instrum.Methods. A417. 230-265 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A.Airapetian et al.: "Measurement of the proton spin structure function g^p_1 with a pure hydrogen target"Phys.Lett.. B442. 484-492 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ackerstaff et al.: "Flavoru asymmetry of the light quark sea from semi-inclusive deep inelastic scattering"Phys.Rev.Lett.. 81. 5519-5523 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ackerstaff et al.: "Determination of deep inelastic contribution to the generalized Gerasimov-Drell-Hearn integral for the proton"Phys.Lett.. B444. 531-538 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ackerstaff et al.: "Flavor decomposition of the polarized quark distribtuions in the nucleon from inclusive and semi-inclusive deep-inelastic scattering"Phys.Lett.. B464. 123-134 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ackerstaff et al.: "Beam-induced nuclear depolarization in a gaseous polarized hydrogen target"Phys.Rev.Lett.. 82. 1164-1168 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ackerstaff et al.: "Observation of a coherence length effent in exclusive ρ^0 electroproduction"Phys.Rev.Lett.. 82. 3025-3029 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A.Airapetian et al.: "Measurement of the spin asymmetry in the photoproduction of pairs of high p_T hadrons at HERMES"Phys.Rev.Lett.. 84. 2584-2588 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A.Airapetion et al.: "Evidence for a single-spin azimuthal asymmetry in semi-inclusive pion electroproduction"Phys.Rev.Lett.. 84. 4047-4051 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] E.Achenauer et al.: "Optical characterization of n=1.03 silica aerogel used as radiator in RICH of HERMES"Nucl.Instrum.Methods. A440. 338 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Ackersraff et al.: "Nuclear effects on R=σ_L/σ_T in deep-inelastic scattering"Phys.Lett.. B475. 386-394 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Airapetian et al.: "Exclusive leptoproduction of ρ^0 mesons on hydrogen at intermediate W values"Eur.Phys.Jour.. C17,3. 389-398 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Airapetian et al.: "The Q^2-dependence of the generalized Gerasimov-Drell-Hearn integral of the proton"Phys.Lett.. B494. 1 (2000)

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

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Published: 2002-03-26  

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