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1995 Fiscal Year Final Research Report Summary

Study of CP Violation in Weak Interaction

Research Project

Project/Area Number 04402006
Research Category

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

Allocation TypeSingle-year Grants
Research Field 核・宇宙線・素粒子
Research InstitutionOsaka University

Principal Investigator

NAGASHIMA Yorikiyo  Osaka Univ., Physics Dept.Professor, 理学部, 教授 (90044768)

Co-Investigator(Kenkyū-buntansha) HAZUMI Masashi  Osaka Univ., Physics Dept.Research Associate, 理学部, 助手 (20263197)
TAKITA Masato  Osaka Univ., Physics Dept.Research Associate, 理学部, 助手 (20202161)
HABA Junji  KEK,Physics Dept.Associate Professor, 物理部, 助教授 (60180923)
YAMANAKA Taku  Osaka Univ., Physics Dept.Associate Professor, 理学部, 助教授 (20243157)
Project Period (FY) 1992 – 1995
KeywordsWeak interaction / CP violation / Neutral kaon / CsI,photomultiplier / Data acquisition system / Photon veto counter / ガンマ線検出器
Research Abstract

We have analyzed the data from Fermilab E731 experiment, and published the final result on the CP violation parameter, Re (epsilon'/epsilon). We have also analyzed the data from Fermilab E799-I experiment, whose purpose was to search for many rare K_L decays. We have published new results on K_L*pi^0ee, K_L*pi^0mumu, K_L*pi^0nunu, K_L*eeee, K_L*eegammagamma, K_L*pi^0pi^0gamma, pi^0*ee, and pi^0*mue. The first three decays are expeted to have a large direct CP violation amplitude.
9.2.Preparation of Fermilab KTeV experiment
Fermilab KTeV experiment will begin in July of 1996, and will run for 2 years. The experiment will measure the CP violation parameter Re (epsilon'/epsilon) with 6 times better accuracy, to 1x10^<-4>. It will also search for many rare K_L decays with a sensitively improved by two orders of magnitudes. We have made the following contributions to the experiment.
*We have worked UCLA and Hamamatsu Photonics to develop a new type of phototubes for the new CsI calorimeter. The tube was designed to have an excellent linearity. We built a new phototube testing system, and measured the linearity and rate dependence of the 2400 tubes with <0.2% accuracy.
*We have collaborated with Fermilab to develop a new data acquisition system. The system consists of a large memory matrix and high performance computers. This system can read in and fully analyze 8kbyte events coming at 20kHz, and write out selected events to tape.
*We have designed, tested, and produced a specialized photon veto counter to be placed around the beam holes in the CsI calorimeter.
*We have estimated the sensitivity and background levels for various rare K_L decays by using Monte Carlo simulation. We have also developped analysis codes for the decays.

  • Research Products

    (26 results)

All Other

All Publications (26 results)

  • [Publications] L. K. Gibbons, et al.: "Measurement of the CP Violation Parameter Re(ε′/ε)" Phys. Rev. Lett.70. 1203-1206 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] D. A. Harris, et al.: "Limit on the Branching Ratio of K_L→π^0ee" Phys. Rev. Lett.71. 3918-3917 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] D. A. Harris, et al.: "A Limit on the Branching Ratio of K_L→π^0μμ" Phys. Rev. Lett.71. 3914-3917 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M. Weaver, et al.: "Limit on the Branching Ratio of K_L→π^0νν" Phys. Rev. Lett.72. 3758-3761 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T. Nakaya, et al.: "Measurement of the Branching Ratio of K_L→e^+e^-γγ" Phys. Rev. Lett.73. 2169-2173 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K. S. McFarland, et al.: "Limit on the Branching Ratio of π^0→ee" Phys. Rev. Lett.71. 3918-3921 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] B.Schwingenheuer et al.: "CPT Tests in the Neutral Kaon System" Phys.Rev.Lett.74. 4376-4379 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.B.Spencer et al.: "Measurement of the Branching Ratio and Form-Factor of K_L*mumugamma" Phys.Rev.Lett.74. 3323-3326 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] E.J.Ramberg et al.: "Polarization of Lambda and Anti-Lambda Produced by 800-GeV Protons" Phys.Lett.B338. 403-408 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Nakaya et al.: "Measurement of the Branching Ratio of K_L*e^+e^-gammagamma" Phys.Rev.Lett.73. 2169-2173 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] D.Roberts et al.: "Search for the decay K_L*pi^0pi^0gamma" Phys.Rev.D50. 1874-1878 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Weaver et al.: "Limit on the Branching Ratio of K_L*pi^0nunu" Phys.Rev.Lett.72. 3758-3761 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] P.Gu et al.: "Measurement of the Branching Ratio and a Study of CP for the Leptonic Decay K_L*e^+e^-e^+e^-" Phys.Rev.Lett.72. 3000-3003 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] P.Krolak et al.: "A Limit on the Lepton-Family Number Violating Process pi^0*mue" Phys.Lett.B320. 407-410 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] D.A.Harris et al.: "A Limit on the Branching Ratio of K_L*pi^0mumu" Phys.Rev.Lett.71. 3914-3917 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] D.A.Harris et al.: "Limit on the Branching Ratio of K_L*pi^0e^+e^-" Phys.Rev.Lett.71. 3918-3921 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.S.-McFarland et al.: "Measurement of the Branching Ratio of pi^0*ee from pi^0s Produced by K_L*pi^0pi^0pi^0Decays in Flight" Phys.Rev.Lett.71. 31-34 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] E.-Ramberg et al.: "Simultaneous Measurement of K_S and K_L Decays into pi^+pi^-gamma" Phys.Rev.Lett.70. 2525-2528 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] E.-Ramberg et al.: "Measurement of the CP violation Parameter eta_<+-gamma> in Neutral Kaon Decays" Phys.Rev.Lett.70. 2529-2532 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] G.Makoff et al.: "Study of the Decay K_L*pi^+pi^0enu" Phys.Rev.Lett.70. 1591-1594 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] L.K.Gibbons et al.: "Measurement of the CP-Violation Parameter Re (epsilon'/epsilon)" Phys.Rev.Lett.70. 1203-1206 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] L.K.Gibbons et al.: "New Measurements of the Neutral Kaon Parameters DELTAm, tau_s, PHI_<00>-PHI_<+->, and PHI_<+->" Phys.Rev.Lett.70. 1199-1202 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] G.E.Graham et al.: "Search for the Decay K_L*pi^0nunu" Phys.Lett.B295. 169-173 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] S.V.Somalwar et al.: "A Measurement of the Quadratic Slope Parameter in the K_L*3pi^0 Decay Dalitz Plot" Phys.Rev.Lett.68. 2580-2583 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] V.Papadimitriou et al.: "A Measurement of the Branching Ratio of the Decay K_L*pi^0gammagamma" Phys.Rev.D44. 573-576 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A.Barker et al.: "New Limit on K_L*pi^0e^+e^-" Phys.Rev.D41. 3546-3547 (1990)

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

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Published: 1997-03-04  

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