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Experimental research on penta-quark baryons with the STB ring

Research Project

Project/Area Number 17340063
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionTohoku University

Principal Investigator

SHIMIZU Hajime  Tohoku University, Graduate School of Science, Professor, 大学院理学研究科, 教授 (20178982)

Co-Investigator(Kenkyū-buntansha) YAMAZAKI Hirohito  Tohoku University, Graduate School of Science, Assistant Professor, 大学院理学研究科, 助手 (90260413)
ISHIKAWA Takatsugu  Tohoku University, Graduate School of Science, Assistant Professor, 大学院理学研究科, 助手 (40400220)
Project Period (FY) 2005 – 2006
Project Status Completed (Fiscal Year 2006)
Budget Amount *help
¥15,200,000 (Direct Cost: ¥15,200,000)
Fiscal Year 2006: ¥7,400,000 (Direct Cost: ¥7,400,000)
Fiscal Year 2005: ¥7,800,000 (Direct Cost: ¥7,800,000)
Keywordspenta-quark / strangeness / U-spin / STB ring / solid deuterium / electromagnetic calorimeter / BSO crystal detector / PWO crystal detector / CsIクリスタル検出器
Research Abstract

We have observed a narrow baryon resonance N^*(1670) in this research project. The mass and the width of the resonance are 1665-1675 MeV/c^2 and 10-40 MeV/c^2,respectively, according to the latest analysis up to now. The resonance bump appeared in the total cross section data obtained in an η meson photoproduction experiment using a solid deuterium target. The bump did not show up in the case with a solid hydrogen target under the same experimental condition. Thus, the new resonance couples to the neutron, but not to the proton through radiative transitions. We examined the spin 1/2 and 3/2 states with both parities, fitting these states to the data one by one. The fitting was made for the data of the total cross section and the cosθ coefficients of the angular distributions. A negative parity state such as S11 or D13 has turned out to reproduce the data better than positive parity states, although it is difficult to determine the spin and parity of the resonance definitely with the present data. However, there are several broad resonances, S11(1650),D15(1675),F15(1680),D13(1700),P11(1700), and P13(1720), the width of which is roughly 100-200 MeV/c^2. And any of these broad resonances is placed over the mass region around 1670 MeV/c^2. The narrow resonance with the same quantum numbers as one of these broad states cannot be constructed as a member of three quark states. Taking the coupling situation of the resonance to the nucleons into account, it is natural, therefore, to regard the narrow resonance as a member of the antidecuplet of pentaquark baryons. Here U-spin conservation allows the process γn→ N^*(1670), but prohibits the transition γp→N^<*^+>(1670). Because the U-spin of γ,n, and p is 0,1,and 1/2,respectively, while that of N^*(1670) is 1 and 3/2 for N^<*^+>(1670) in the antidecuplet.

Report

(3 results)
  • 2006 Annual Research Report   Final Research Report Summary
  • 2005 Annual Research Report
  • Research Products

    (21 results)

All 2006 2005

All Journal Article (21 results)

  • [Journal Article] Differential cross section and photon-beam asymmetry for the γn→K^+Σ^- reaction at Eγ=1.5-2.4 GeV2006

    • Author(s)
      H.Kohri et al.
    • Journal Title

      Phys. Rev. Lett. 97

      Pages: 82003-82003

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Photoproduction of η-mesons off C and Cu nuclei for photon energies below 1.1 GeV2006

    • Author(s)
      T.Kinoshita et al.
    • Journal Title

      Phys. Lett. B639

      Pages: 429-429

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Photoproduction of η mesons off protons for E_γ【less than or equal】1.15 GeV2006

    • Author(s)
      T.Nakabayashi et al.
    • Journal Title

      Phys. Rev. C74

      Pages: 35202-35202

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] The γp→K^+Λ and γp→K^+Σ^0 reaction at forward angles with photon energies form 1.5 to 2.4 GeV2006

    • Author(s)
      M.Sumihama et al.
    • Journal Title

      Phys. Rev. C73

      Pages: 35214-35214

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] The γp→K^+Λ and γp→K^+Σ^0 reactions at forward angles with photon energies from 1.5 to 2.4 GeV2006

    • Author(s)
      M.Sumihama et al.
    • Journal Title

      Phys.Rev.C 73

      Pages: 35214-35214

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Differential cross section and photon-beam asymmetry for the γn→K^+Σ^-reaction at Eγ=1.5-2.4 GeV2006

    • Author(s)
      H.Kohri et al.
    • Journal Title

      Phys.Rev.Lett. 97

      Pages: 82003-82003

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Photoproduction of η-mesons off C and Ct nuclei for photon energies below 1.1 GeV2006

    • Author(s)
      T.Kinoshita et al.
    • Journal Title

      Phys.Lett.B 639

      Pages: 429-429

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Photoproduction of η mesons off protons for E_γ【less than or equal】1.15 GeV2006

    • Author(s)
      T.Nakabayashi
    • Journal Title

      Phys.Rev.C 74

      Pages: 35202-35202

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] The γρ→K^+Λ and γρ→K^+Σ^0 reactions at forward angles with photon energies from 1.5 to 2.4 GeV2006

    • Author(s)
      M.Sumihama, et al.
    • Journal Title

      Phys. Rev. C73

      Pages: 35214-35214

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Photoproduction of η-mesons off C and Cu nuclei for photon energies below 1.1 GeV2006

    • Author(s)
      T.Kinoshita, et al.
    • Journal Title

      Phys. Lett. B639

      Pages: 429-429

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Differential cross section and photon-beam asymmetry for the γn→K^+Σ^- reaction at E_γ=1.5-2.4 GeV2006

    • Author(s)
      H.Kohri, et al.
    • Journal Title

      Phys. Rev. Lett. 97

      Pages: 82003-82003

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Photoproduction of η mesons off protons for E_γ*1.15 GeV2006

    • Author(s)
      T.Nakabayashi, et al.
    • Journal Title

      Phys. Rev. C74

      Pages: 35202-35202

    • Related Report
      2006 Annual Research Report
  • [Journal Article] First beam test on a BSO electromagnetic calorimeter2005

    • Author(s)
      H.Shimizu et al.
    • Journal Title

      Nucl. Instr. and Meth. A550

      Pages: 258-258

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] φ photo-production from Li, C, Al and Cu nuclei at Eγ=1.5-2.4 GeV2005

    • Author(s)
      T.Ishikawa et al.
    • Journal Title

      Phys. Lett. B608

      Pages: 215-215

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Near-threshold diffractive φ-meson photoproduction from the proton2005

    • Author(s)
      T.Mibe et al.
    • Journal Title

      Phys. Rev. Lett. 95

      Pages: 182001-182001

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] First beam test on a BSO electromagnetic calorimeter2005

    • Author(s)
      H.Shimizu et al.
    • Journal Title

      Nucl.Instr.and Meth.A 550

      Pages: 258-258

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] φ photo-production from Li,C,Al and Cu nuclei at Eγ=1.5-2.4 GeV2005

    • Author(s)
      T.Ishikawa et al.
    • Journal Title

      Phys.Lett.B 608

      Pages: 215-215

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] Near-threshold diffractive φ-meson photoproduction from the proton2005

    • Author(s)
      T.Mibe et al.
    • Journal Title

      Phys.Rev.Lett. 95

      Pages: 182001-182001

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary
  • [Journal Article] First beam test on a BSO electromagnetic calorimeter2005

    • Author(s)
      H.Shimizu, et al.
    • Journal Title

      Nucl.Instr.And Meth. A550

      Pages: 258-258

    • Related Report
      2005 Annual Research Report
  • [Journal Article] φ photo-production from Li, C, Al and Cu nuclei at Eγ=1.5-2.4 GeV2005

    • Author(s)
      T.Ishikawa, et al.
    • Journal Title

      Phys.Lett. B608

      Pages: 215-215

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Near-threshold diffractive φ-meson photoproduction from the proton2005

    • Author(s)
      T.Mibe, et al.
    • Journal Title

      Phys.Rev.Lett. 95

      Pages: 182001-182001

    • Related Report
      2005 Annual Research Report

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Published: 2005-04-01   Modified: 2016-04-21  

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