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2016 Fiscal Year Annual Research Report

Probing the neutrino mass hierarchy with atmospheric neutrinos and developing the next-generation research frontier

Planned Research

Project AreaUnification and Development of the Neutrino Science Frontier
Project/Area Number 25105004
Research InstitutionThe University of Tokyo

Principal Investigator

塩澤 真人  東京大学, 宇宙線研究所, 教授 (70272523)

Co-Investigator(Kenkyū-buntansha) 鈴木 州  神戸大学, 理学研究科, 助教 (20243298)
早戸 良成  東京大学, 宇宙線研究所, 准教授 (60321535)
横山 将志  東京大学, 大学院理学系研究科(理学部), 准教授 (90362441)
Project Period (FY) 2013-06-28 – 2018-03-31
Keywordsニュートリノ / 核子崩壊 / ニュートリノ天文学
Outline of Annual Research Achievements

本研究では大気ニュートリノ観測データを用いたニュートリノ振動研究と、次世代基幹実験ハイパーカミオカンデ実現のための包括的な準備研究を行う。
前者の大気ニュートリノ研究では、これまでに開発したニュートリノと反ニュートリノの統計的分離を導入し、最新の観測データも追加して、ニュートリノ振動研究の結果をまとめた。ここで子炉実験とT2Kの振動測定結果を束縛条件として加えた。未解明の質量階層構造について、Δχ2 = χ2(順階層) -χ 2(逆階層) = -5.2 が得られ、 逆階層性が正しいとした場合、Δχ 2 が -5.2以下になる確率は2.4%以下 (sin2θ23=0.6) および0.4%以下 (sin2θ23=0.4)と小さいことがわかり、順階層構造を示唆する結果を得た。またCP対称性の破れに関しては最大のδ~-π/2がベストフィットとして得られ、T2Kの結果を支持していることがわかった。
ハイパーカミオカンデ準備研究では、弾性波トモグラフィー調査より岩盤等級の3Dマップを広域で作成し、破砕帯を避けた、岩質の良好な場所(200m x 150m)を特定し、建設候補地を絞り込みかつ空洞成立性を確認した。また工期8年と見積もった。並行して新たに開発した高感度光センサーを約100本生産し、スーパーカミオカンデにおける長期性能実証試験の準備を行った。本計画は、日本学術会議の第23期学術の大型計画に関するマスタープラン(2017)において「重点大型研究計画」の一つに選ばれ、文科省による予算措置に係るロードマップ2017に審査資料を提出した。東京大学内では概算要求の準備をしつつ、プロジェクト推進の中核となる推進機構の設置の準備をおこなった。

Current Status of Research Progress
Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

大気ニュートリノを用いたニュートリノ振動研究で世界最高感度での研究成果をまとめたことから、研究が当初計画通りに順調に進展しているとみなせる。ハイパーカミオカンデの準備研究では、大空洞の成立性確認と高感度光センサーの開発に成功した。プロジェクト成立に最も重要な要素の開発が成功し、実施計画を順当にまとめることに成功した。さらに日本学術会議により重点大型計画に選ばれたことは、プロジェクトの実現に向けて大きなマイルストーンとなる。

Strategy for Future Research Activity

大気ニュートリノ振動研究においては、順階層構造と逆階層構造の両仮説を用いたp-valueを計算して結果をまとめる。また論文にまとめる。
ハイパーカミオカンデに関しては、100個の高感度光センサーのスーパーカミオカンデでの長期試験の準備を進める。国際協力体制、東大内推進体制、KEK協力関係の整備をさらに進めていく。また概算要求を始めるとともに、建設開始に備えた技術的準備を進める。

  • Research Products

    (31 results)

All 2017 2016 Other

All Int'l Joint Research (6 results) Journal Article (4 results) (of which Int'l Joint Research: 4 results,  Peer Reviewed: 4 results,  Open Access: 2 results) Presentation (16 results) (of which Int'l Joint Research: 16 results,  Invited: 15 results) Remarks (2 results) Funded Workshop (3 results)

  • [Int'l Joint Research] Boston University/University of California, Davis/University of California, Irvine(米国)

    • Country Name
      U.S.A.
    • Counterpart Institution
      Boston University/University of California, Davis/University of California, Irvine
    • # of Other Institutions
      13
  • [Int'l Joint Research] University of British Columbia/University of Regina/TRIUMF(Canada)

    • Country Name
      Canada
    • Counterpart Institution
      University of British Columbia/University of Regina/TRIUMF
    • # of Other Institutions
      3
  • [Int'l Joint Research] Chonnam National University/Dongshin University/GIST College(韓国)

    • Country Name
      KOREA (REP. OF KOREA)
    • Counterpart Institution
      Chonnam National University/Dongshin University/GIST College
    • # of Other Institutions
      3
  • [Int'l Joint Research] IRFU, CEA/Ecole Polytechnique(France)

    • Country Name
      France
    • Counterpart Institution
      IRFU, CEA/Ecole Polytechnique
  • [Int'l Joint Research] University of Edinburgh/Imperial College London/Lancaster University(英国)

    • Country Name
      UNITED KINGDOM
    • Counterpart Institution
      University of Edinburgh/Imperial College London/Lancaster University
    • # of Other Institutions
      6
  • [Int'l Joint Research]

    • # of Other Countries
      9
  • [Journal Article] Search for proton decay via p→e+π0 and p→μ+π0 in 0.31 megaton・years exposure of the Super-Kamiokande water Cherenkov detector2017

    • Author(s)
      Super-Kamiokande collaboration
    • Journal Title

      Physical Review D

      Volume: 95 Pages: 012004

    • DOI

      10.1103/PhysRevD.95.012004

    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] NUISANCE: a neutrino cross-section generator tuning and comparison framework2017

    • Author(s)
      Stowell P.、Wret C.、Wilkinson C.、Pickering L.、Cartwright S.、Hayato Y.、Mahn K.、McFarland K.S.、Sobczyk J.、Terri R.、Thompson L.、Wascko M.O.、Uchida Y.
    • Journal Title

      Journal of Instrumentation

      Volume: 12 Pages: P01016~P01016

    • DOI

      10.1088/1748-0221/12/01/P01016

    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] SEARCH FOR NEUTRINOS IN SUPER-KAMIOKANDE ASSOCIATED WITH GRAVITATIONAL-WAVE EVENTS GW150914 AND GW1512262016

    • Author(s)
      Super-Kamiokande collaboration
    • Journal Title

      The Astrophysical Journal

      Volume: 830 Pages: L11~L11

    • DOI

      10.3847/2041-8205/830/1/L11

    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Testing charged current quasi-elastic and multinucleon interaction models in the NEUT neutrino interaction generator with published datasets from the MiniBooNE and MINERνA experiments2016

    • Author(s)
      Hayato Y.他
    • Journal Title

      Physical Review D

      Volume: 93 Pages: 072010

    • DOI

      doi.org/10.1103/PhysRevD.93.072010

    • Peer Reviewed / Int'l Joint Research
  • [Presentation] Recent results and future prospects of neutrino oscillation experiments2017

    • Author(s)
      Roger Wendell
    • Organizer
      The 3rd KMI International Symposium on the Origin of Particles and the Universe (KMI 2017)
    • Int'l Joint Research / Invited
  • [Presentation] Super-Kamiokande2017

    • Author(s)
      Masato Shiozawa
    • Organizer
      XVII International Workshop on Neutrino Telescope
    • Int'l Joint Research / Invited
  • [Presentation] Japan-based neutrino program2017

    • Author(s)
      Masato Shiozawa
    • Organizer
      XVII International Workshop on Neutrino Telescope
    • Int'l Joint Research / Invited
  • [Presentation] New 50 cm Photo-Detectors for Hyper-Kamiokande2016

    • Author(s)
      Yasuhiro Nishimura
    • Organizer
      38th International Conference on High Energy Physics (ICHEP 2016)
    • Int'l Joint Research
  • [Presentation] Development for a High-Resolution 50 cm Photodetector for Hyper-Kamiokande2016

    • Author(s)
      Yasuhiro Nishimura
    • Organizer
      International Workshop on Next Generation Nucleon Decay and Neutrino Detectors (NNN16)
    • Int'l Joint Research / Invited
  • [Presentation] Large PMT R&D in Japan2016

    • Author(s)
      Yasuhiro Nishimura
    • Organizer
      International Workshop on Next Generation Nucleon Decay and Neutrino Detectors (NNN16)
    • Int'l Joint Research / Invited
  • [Presentation] Atmospheric Neutrino Oscillation2016

    • Author(s)
      Kimihiro Okumura
    • Organizer
      International Workshop on Next Generation Nucleon Decay and Neutrino Detectors (NNN16)
    • Int'l Joint Research / Invited
  • [Presentation] New atmospheric and solar neutrino results from Super-Kamiokande2016

    • Author(s)
      Shigetaka Moriyama
    • Organizer
      XXVII Interna- tional Conference on Neutrino Physics and Astro- physics (Neutrino 2016)
    • Int'l Joint Research / Invited
  • [Presentation] Super-K upgrade and Hyper-Kamiokande2016

    • Author(s)
      Shoei Nakayama
    • Organizer
      The 9th International Workshop on Ring Imaging Cherenkov Detectors (RICH 2016)
    • Int'l Joint Research / Invited
  • [Presentation] Hyper-Kamiokande project - detector status and LBL physics potential -2016

    • Author(s)
      Masato Shiozawa
    • Organizer
      Third Int. Meeting for Large Neutrino Infrastructures
    • Int'l Joint Research / Invited
  • [Presentation] Hyper-Kamiokande detector design and calibration2016

    • Author(s)
      Hidekazu Tanaka
    • Organizer
      International Workshop on Next Generation Nucleon Decay and Neutrino Detectors (NNN16)
    • Int'l Joint Research / Invited
  • [Presentation] Hyper-Kamiokande2016

    • Author(s)
      Masashi Yokoyama
    • Organizer
      Prospects in Neutrino Physics (NuPhys 2016)
    • Int'l Joint Research / Invited
  • [Presentation] Exploring the Universe with Elusive Neutrinos, from 1000m Underground2016

    • Author(s)
      Masashi Yokoyama
    • Organizer
      IOP Publishing Young Researchers' Meeting: Frontiers in Fundamental and Applied Physics
    • Int'l Joint Research / Invited
  • [Presentation] Overview of neutrino-nucleus interactions( From an experimentalist’s point of view )2016

    • Author(s)
      Yoshinari Hayato
    • Organizer
      International Workshop on Next Generation Nucleon Decay and Neutrino Detectors (NNN16)
    • Int'l Joint Research / Invited
  • [Presentation] Beyond SM physics with Super-Kamiokande2016

    • Author(s)
      Yoshitaka Itow
    • Organizer
      Beyond the Standard Model with Neutrino Detectors" (BSMND 2016)
    • Int'l Joint Research / Invited
  • [Presentation] Results of proton decay and N-Nbar oscillation2016

    • Author(s)
      Shunichi Mine
    • Organizer
      International Workshop on Next Generation Nucleon Decay and Neutrino Detectors (NNN16)
    • Int'l Joint Research / Invited
  • [Remarks] ハイパーカミオカンデ

    • URL

      http://www.hyper-k.org

  • [Remarks] Hyper-Kamiokande

    • URL

      http://www.hyperk.org

  • [Funded Workshop] Workshop on Supernova at Hyper-Kamiokande2017

  • [Funded Workshop] 4th Hyper-Kamiokande Proto-Collaboration Meeting2017

  • [Funded Workshop] 3rd Hyper-Kamiokande Proto-Collaboration Meeting2016

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Published: 2018-12-17   Modified: 2022-02-22  

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