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Study of deeply-bound pionic atoms

Research Project

Project/Area Number 09440100
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 素粒子・核・宇宙線
Research InstitutionTHE UNIVERSITY OF TOKYO

Principal Investigator

HAYANO Ryugo  THE UNIVERSITY OF TOKYO,Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (30126148)

Co-Investigator(Kenkyū-buntansha) HIRENZAKI Satoru  Nara Women's University, Department of Physics, Associate Professor, 理学部, 助教授 (60283925)
Project Period (FY) 1997 – 1998
Project Status Completed (Fiscal Year 1998)
Budget Amount *help
¥13,100,000 (Direct Cost: ¥13,100,000)
Fiscal Year 1998: ¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 1997: ¥7,400,000 (Direct Cost: ¥7,400,000)
KeywordsPion / Exotic Atom / Deeply-bound states / Effective mass in nuclei / Nuclear reaction / Eta meson / Omega meson / GSI / 中間子原子 / 量子色力学(QCD) / パイ(π)中間子 / エータ(η)中間子 / オメガ(ω)中間子 / 原子核実験 / GSI研究所 / 重陽子
Research Abstract

The purpose of the research is to study theoretically as well as experimentally the deeply-bound pionic atom states, in particular is and 2p states, and to obtain information on the effective pion mass in nuclei. We also developed a new method to study the in-medium masses of eta and omega mesons. The major achievements during the two years are as follows :
1. In order to search for the is bound state of pionic atom, we carried out an experiment using the ^<206>Pb(d, ^3He) reaction. The wavefunction of the pionic is state bound to a heavy nucleus has a large overlap with the nucleus, hence suitable to study the behavior of pions in nuclei. However, no such states have been experimentally observed. Theoretical studies have suggested that it is possible to identify 2p as well as is states as clear peaks in the excitation-energy spectrum, if Pb2O6 is chosen as the target. We therefore carried out the expriment, and successfully observed the 2p and is peaks. When the detailed analysis, being carried out, is completed, we expect to determine the pion effective mass with a high precision.
2. The success of the pionic atom experiment motivated us to study the feasibility of studying the behavior of other mesons, such as eta and omega, by using the recoilless (d, ^3He) reaction. We first estimated the meson-nucleus optical potential, and determined the binding energies and widths of mesons by solving the Klein-Gordon equation. In both cases, the potentials were strongly attractive, and the existence of bound states are predicted. We then used the Green function method and the Eikonal approximation to estimate the reaction cross sections. We found that the bound-state peaks can be observed, even after taking account of various background processes. An experimental proposal based on this study was submitted to GSI, and was approved as S214.

Report

(3 results)
  • 1998 Annual Research Report   Final Research Report Summary
  • 1997 Annual Research Report
  • Research Products

    (17 results)

All Other

All Publications (17 results)

  • [Publications] R.S.Hayano et al.: "Formation of η/ω-mesic nuclei using the recoilless (d,^3He) reaction" The European Physical Journal A. (印刷中). (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] N.Nose-Togawa et al.: "Nuclear quadrupole effects in deeply bound pionic atoms" Nuclearl Physics. A623. 548-558 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] S.Hirenzaki and H.Toki: "Neutron pick-up pion transfer reactions for the formation of deeply bound pionic atoms in ^<208>Pb" Nuclear Physics. A628. 403-416 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] R.S.Hayano et al.: "Formation of η/ω-mesic nuclei using the recoilless (d,^3He) reaction" Proceedings of “Mesons and Light Nuclei" Prague,1998. (印刷中). (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] R.S.Hayano et al.: "Search for bound η and ω nuclear states using the recoilless (d,^3He) reaction-Study of Meson Mass Shifts in Nuclei-" GSI Research Proposal. S214. 1-15 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] T.Yamazaki et al.: "Effective pion mass in the nuclear medium deduced from deeply bound pionic states in ^<207>Pb" Physics Letters. B418. 246-251 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] R.S.Hayano et al.: "Formation of eta/omega-mesic nuclei using the recoilless (d, ^3He) reaction" The european physical journal A. (in press). (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] N.Nose-Togawa, et al.: "Nuclear quadrupole effects in deeply bound pionic atoms" Nucl.Phys.A623. 548-558 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] S.Hirenzaki and H.Toki: "Neutron pick-up pion transfer reactions for the formation of deeply bound pionic atoms in ^<208>Pb" Nucl.Phys.A628. 403-416 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] R.S.Hayano et al.: "Formation of eta/omega-mesic nuclei using the recoilless (d, ^3He) reaction" Invited talk at "Mesons and Light Nuclei" (Prague, 1998) , proceedings. (in print).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] R.S.Hayano et al.: "Search for bound eta and omega nuclear states using the recoilless (d, ^3He) reaction-Study of Meson Mass Shifts in Nuclei-" GSI Research Proposal. S214. 1-15 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] T.Yamazaki et al.: "Effective pion mass in the nuclear medium deduced from deeply bound pionic states in ^<207>Pb" Physics Letters. B418. 246-251 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] R.S.Hayano et al.: "Formation of η/ω-mesic nuclei using the recoilless (d,^3He) reaction" The European Physical Journal A. (印刷中). (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] S.Hirenzaki and H.Toki: "Neutron pick-up pion transfer reactions of the formation of deeply bound pionic atoms in ^<208>Pb" Nuclear Physics. A628. 403-416 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] R.S.Hayano et al.: "Formation of η/ω-mesic nuclei using the recoilless (d,^3He) reaction" Proceedings of "Mesons and Light Nuclei" Prague,1998. (印刷中). (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] T.Yamazaki et al.: "Effective pion mass in the nuclear medium deduced from deeply bound pionic states in ^<207>Pb" Physics letters. B418. 246-251 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] Hayano,Hirenzaki他: "SEARCH FOR BOUND η-AND ω-NUCLEAR STATES USING THE RECOILLESS (d,3He) REACTION" GSI Research Proposal (approved). S-214. 1-10 (1997)

    • Related Report
      1997 Annual Research Report

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Published: 1997-04-01   Modified: 2016-04-21  

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