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Study of neutrino oscillations using solar neutrinos

Research Project

Project/Area Number 08640351
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 素粒子・核・宇宙線
Research InstitutionUniversity of Tokyo

Principal Investigator

NAKAHATA Masayuki  ICRR Univ.of Tokyo, Assistant professor, 宇宙線研究所, 助教授 (70192672)

Co-Investigator(Kenkyū-buntansha) MIURA Makoto  ICRR Univ.of Tokyo, Research Associate, 宇宙線研究所, 助手 (10272519)
FUKUDA Yoshiyuki  ICRR Univ.of Tokyo, Research Assciate, 宇宙線研究所, 助手 (40272520)
Project Period (FY) 1996 – 1997
Project Status Completed (Fiscal Year 1997)
Budget Amount *help
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywordsneutrino / solar neutrino / neutrino oscillations / Super-Kamiokande / LINAC
Research Abstract

In this research, the neutrino oscillations were studied using the Super-Kamiokande which was start from April 1996. The Super-Kamiokande detector observes solar neutrinos using neutrino-electron scatterings. The Super-Kamiokande detector has a fiducial volume of 22,000 tons and it is able to detect world largest number of solar neutrino events (10-20 events per day). Hence, it is able to study day/night difference of the solar neutrino flux and distortion of energy spectrum. They are purely due to the property of neutrinos and they are free from any ambiguities of solar models. The most crucial thing in this research was the energy calibration of the detector. We have calibrated the detector using an electron linear accelerator (LINAC). We have achieved an accuracy of better than 1 % in the absolute energy scale. Using the date taken in 1996 and 1997, we have processed 374 days' date. The flux obtained from the data sample is 35.8 % of the expectation from the standard solar model. The results reconfirmed the "solar neutrino problem" with an unprecedented statistics. At the moment, however, no significant difference between fluxes between dattime and nighttime is observed. And the shape of the energy spectrum is statistically consistent with the expectation at the moment. If we have few more years of data, we can discuss neutrino oscillations using day/night difference and the energy spectrum.

Report

(3 results)
  • 1997 Annual Research Report   Final Research Report Summary
  • 1996 Annual Research Report

Research Products

(13 results)

All Other

All Publications

  • [Publications] Y.Fukuda et al.: "Solar Neutrino Data Covering Solar Cycle 22" Physical Review Letters. 77. 1683-1686 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] M.Nakahata: "Super Kamiokande" Eighth Rencontres de Blois. 129-138 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Takeuchi: "The First Results from Super-Kamiokande" Proceedings of the XXXllnd Rencontres De Moriond. 335-342 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] M.Nakahata: "Neutrino masses and oscillations" Proceedings of the International Europhysics Conference on High Energy. (作制中). (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Fukuda et al.: ""Solar neutrino data covering solar cycle 22"" Physical Review Letters. 77. 1683-1686 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] M.Nakahata: ""Super Kamiokande"" Eight Recontres de Blois. 129-138 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Takeuchi: ""The First Results from Super-Kamiokande"" Proceedings of XXXIInd Recontres de MORIOND. 335-342 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] M.Nakahata: ""Neutrino masses and oscillations"" Proceedings of the International Europhysics Conference on High Energy. (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Fukuda et al.: "Solar Neutrino Data Covering Solar Cycle 22" Physical Review Letters. 77. 1683-1686 (1996)

    • Related Report
      1997 Annual Research Report
  • [Publications] M.Nakahata: "Super Kamiokande" Eighth"Rencontres de Blois". 129-138 (1996)

    • Related Report
      1997 Annual Research Report
  • [Publications] Y.Takeuchi: "The First Results from Super-Kamiokande" Proceedings of the XXXIInd Rencontres De MORIOND. 335-342 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] M.Nakahata: "Neutrino masses and oscillations" Prodeedings of the International Europhysics Conference on High Energy. (作製中). (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] Y.Fukuda et al.: "Solar Neutrino Data Covering Solar Cycle 22" Physical Review Letters. 77. 1683-1686 (1996)

    • Related Report
      1996 Annual Research Report

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Published: 1996-03-31   Modified: 2016-04-21  

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