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1992 Fiscal Year Final Research Report Summary

Study of K^+ meson production with electromagnetic probes

Research Project

Project/Area Number 02452019
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 核・宇宙線・素粒子
Research InstitutionTOKOKU UNIVERSITY

Principal Investigator

MAEDA Kazushige  Tokoku University, College of General Education, Associate Professor, 教養部, 助教授 (20125652)

Co-Investigator(Kenkyū-buntansha) SAKAGUCHI Atushi  Hiroshima University, Department of Physics,, Research Associate, 理学部, 助手 (70205730)
TERASAWA Tatuo  Tokoku University, Department of Physics, Associate Professor, 理学部, 助手 (40004436)
SUDA Toshimi  Tokoku University, College of General Education, Research Associate, 教養部, 助手 (30202138)
MIYASE Haruhisa  Tokoku University, College of General Education, Professor, 教養部, 助教授 (40005822)
Project Period (FY) 1990 – 1992
KeywordsKaon / Photon / Quasifree / Strangeness / Tagging
Research Abstract

Experimental observations of K^+ photoproduction on nuclei to study hypernuclear spectroscopy and the nuclear strangeness have been considered complementary to that of hadronic probes. An advantage of the (gamma,K^+) reaction compared with other possible reactions in studying the nuclear strangeness is on relatively long mean-free path of gamma and K^+ in the nuclear matter. This feature makes us possible to study the behavior of nucleons and a hyperon in the nuclear interior with less deformation. The (pi^+,K^+) reactions, which are same kinematical condition as the (gamma,K^+) reaction, have established shell structure of the LAMBDA hypernuclei. These achievements done by the hadronic probes must be joined with the electromagnetic process of (gamma,K^+) and (e,e'K^+) reactions to get the unified recognition of the hypernuclei and the nuclear strangeness production. Kaon photoproduction on nuclei has not been done because of lack of the suitable facilities. The project of CEBAF will p … More ermit the detailed exploration of the nuclear strangeness in a few years.
The measurement of the ^<12>C(gamma,K^+) reaction was carried out by using the tagged photon facilities at the 1.3 GeV electron synchrotron of the Institute for Nuclear Study, University of Tokyo. The 1.2 GeV electron beam extracted from the synchrotron was introduced to the photon tagging system with a duty factor of 10%. Photon beam in an energy range of 0.7-1.1 GeV were tagged by a set of 32ch tagging hodoscopes with an energy resolution of 10 MeV.
The events of charged particles were measured by the magnetic spectrometer based on the TAGX system. Fast trigger counters and a TOF wall were installed to identify the leading particles. Two sets of the Silicon Strip Detectors (SSD) with lmm spatial resolution were used to improve the tracking resolution. The K^+ events were selected by the mass spectrum. Contaminations of the pion and proton events are estimated less than 5%. Obtained ^<12>C(gamma,K^+) cross section (preliminary). was compared with the p(gamma,K^+) cross sections. Since the E_<gamma> dependence of the K^+ yield behaves similar to that of the elementary process, the quasi-free process is considered to be dominant. The effective proton number N_<eff>=3.5, which is the number of the participating protons in the ^<12>C(gamma,K^+) reaction have been deduced. Comparing with the N_<eff>=1.7, which was obtained by ^<12>C(pi,K^+) reaction, the photo-Kaon process can be recognized a good probe to investigate the inside of nuclei. Less

  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] S.Asano et al: "Study of the ^<12>c(γ.K^+)X Reaction with Tagged Photons" Annnal Report 1992(東大・原子核研究所. (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] S.Asano et al.: "Quasi Free K^+ production from ^<12>C(γ,K^+)X Reaction" Continbution Paper of PANIC XIII. (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Maeda et al.: "A Study of the 12C(gamma,K+) Reaction with Tagged Photons." 20th INS International Symposium on Hypernuclear and Strange Particle Physics, Shimoda. 64 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Maeda et al.: "Photo-meson productions above the DELTA resonance" Proceedings of the Workshop on Electron Scattering Experiments with Internal Targets. 79 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Maeda: "Nuclear Photo-meson production in the L GeV Energy Region" Genshikaku Kenkyu. Vol.35. 45 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.Asanoet al.: "A Study of the 12C(gamma,K+) Reaction with Tagged Photons." Annual Report, Institute for nuclear Study. 74 (1990)

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

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Published: 1994-03-24  

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