• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to previous page

Search for neutral and light new-particles through Kaon decays

Research Project

Project/Area Number 17K05479
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Research Field Particle/Nuclear/Cosmic ray/Astro physics
Research InstitutionHigh Energy Accelerator Research Organization

Principal Investigator

Komatsubara Takeshi  大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 教授 (30242168)

Project Period (FY) 2017-04-01 – 2020-03-31
Project Status Completed (Fiscal Year 2019)
Budget Amount *help
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2017: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
KeywordsK中間子 / 崩壊 / 稀崩壊 / 新粒子探索 / フレーバー物理 / ダーク / 素粒子実験 / 加速器 / 大強度陽子ビーム
Outline of Final Research Achievements

We search for neutral and light new-particles X0 that appear through a two-body decay of long-lived neutral K meson, KL→π0X0, in the KOTO experiment at the Hadron Experimental Facility of Japan Proton Accelerator Research Complex, J-PARC. Based on the analysis of the data taken in 2015, new results on the KL→π0X0 decay were obtained and published. From the anaysis of the data taken in 2016-2018, we observed four candidate events in the signal region. Currently we are doing further checks on the four events and careful examinations on their origin.

Academic Significance and Societal Importance of the Research Achievements

平成27年のデータをもとに得られたKL→π0X0崩壊の分岐比に対する上限値、X0の質量が135MeVの場合に90%の信頼水準で 4.2億回に一度、はこの崩壊に対する世界で最も低く厳しい値です。平成28-30年のデータで観測された四つの候補事象は、現在の分岐比の感度ではKL→π0νν崩壊ではなくKL→π0X0崩壊と解釈するのが自然です。いずれも、学術的意義が高く、自然法則の深い理解へさらに歩を進める結果です。

Report

(4 results)
  • 2019 Annual Research Report   Final Research Report ( PDF )
  • 2018 Research-status Report
  • 2017 Research-status Report
  • Research Products

    (32 results)

All 2019 2017 Other

All Int'l Joint Research (12 results) Journal Article (1 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 1 results,  Open Access: 1 results) Presentation (6 results) (of which Int'l Joint Research: 4 results,  Invited: 4 results) Remarks (13 results)

  • [Int'l Joint Research] シカゴ大学/ミシガン大学/アリゾナ州立大学(米国)

    • Related Report
      2019 Annual Research Report
  • [Int'l Joint Research] 国立台湾大学(その他の国・地域)

    • Related Report
      2019 Annual Research Report
  • [Int'l Joint Research] 全北大学校/済州大学校/高麗大学校(韓国)

    • Related Report
      2019 Annual Research Report
  • [Int'l Joint Research] JINR(ロシア連邦)

    • Related Report
      2019 Annual Research Report
  • [Int'l Joint Research] シカゴ大学/ミシガン大学/アリゾナ州立大学(米国)

    • Related Report
      2018 Research-status Report
  • [Int'l Joint Research] 国立台湾大学(その他の国・地域)

    • Related Report
      2018 Research-status Report
  • [Int'l Joint Research] 全北大学校/済州大学校/高麗大学校(韓国)

    • Related Report
      2018 Research-status Report
  • [Int'l Joint Research] JINR(ロシア連邦)

    • Related Report
      2018 Research-status Report
  • [Int'l Joint Research] シカゴ大学/ミシガン大学/アリゾナ州立大学(米国)

    • Related Report
      2017 Research-status Report
  • [Int'l Joint Research] 国立台湾大学(台湾)

    • Related Report
      2017 Research-status Report
  • [Int'l Joint Research] 全北大学校/済州大学校/高麗大学校(韓国)

    • Related Report
      2017 Research-status Report
  • [Int'l Joint Research] JINR(ロシア連邦)

    • Related Report
      2017 Research-status Report
  • [Journal Article] Search for KL→π0νν-bar and KL→π0X0 Decays at the J-PARC KOTO Experiment2019

    • Author(s)
      J. K. Ahn et al. (KOTO Collaboration)
    • Journal Title

      Physical Review Letters

      Volume: 122 Issue: 2 Pages: 021802-021802

    • DOI

      10.1103/physrevlett.122.021802

    • Related Report
      2018 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Presentation] Search for the rare decay KL→π0νν at J-PARC KOTO experiment2019

    • Author(s)
      篠原智史(京都大学理学研究科-KOTO実験グループを代表しての発表)
    • Organizer
      「International Conference on Kaon Physics 2019 (Kaon2019)」国際会議
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Recent Results from KOTO Experiment2019

    • Author(s)
      Yu-Chen Tung(シカゴ大学-KOTO実験グループを代表しての発表)
    • Organizer
      「XXXIX International Symposium on Physics in Collision (PIC 2019)」国際会議
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Recent Result on the Measurement of KL→π0νν at the J-PARC KOTO Experiment2019

    • Author(s)
      Chieh Lin(国立台湾大-KOTO実験グループを代表しての発表)
    • Organizer
      「J-PARC Symposium 2019」国際会議
    • Related Report
      2019 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Recent news from KL→π0ννand Perspectives KOTO2019

    • Author(s)
      南條創(大阪大学理学研究科-KOTO実験グループを代表しての発表)
    • Organizer
      「Rencontres de Moriond Electroweak Interactions and Unified Theories (EW) 2019」国際会議
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] J-PARC KOTO実験 2016, 2017, 2018年物理ランにおける背景事象見積もりの研究2019

    • Author(s)
      篠原智史(京都大学理学研究科-KOTO実験グループを代表しての発表)
    • Organizer
      日本物理学会第74回年次大会
    • Related Report
      2018 Research-status Report
  • [Presentation] K中間子の稀な崩壊による中性で軽い新粒子の探索2017

    • Author(s)
      小松原健
    • Organizer
      日本物理学会2017年秋季大会(宇都宮大学峰キャンパス(栃木県宇都宮市))
    • Related Report
      2017 Research-status Report
  • [Remarks] 素粒子原子核研究所「2019年5月の活動報告 : KOTO実験グループ」

    • URL

      https://www2.kek.jp/ipns/ja/report/2019/05-1/

    • Related Report
      2019 Annual Research Report
  • [Remarks] 素粒子原子核研究所「2020年2月の活動報告 : KOTO実験グループ」

    • URL

      https://www2.kek.jp/ipns/ja/report/2020/02-2/

    • Related Report
      2019 Annual Research Report
  • [Remarks] 第14回(2020年)日本物理学会若手奨励賞を素核研の中桐洸太博士研究員と門内晶彦博士研究員が受賞

    • URL

      https://www2.kek.jp/ipns/ja/post/2020/03/20200331/

    • Related Report
      2019 Annual Research Report
  • [Remarks] 素粒子原子核研究所「中性K中間子の稀な崩壊で世界最高感度を10倍更新」

    • URL

      https://www2.kek.jp/ipns/ja/post/2018/07/koto/

    • Related Report
      2018 Research-status Report
  • [Remarks] 素粒子原子核研究所「2018年9月の活動報告 : KOTO実験グループ」

    • URL

      https://www2.kek.jp/ipns/ja/report/2018/09-1/

    • Related Report
      2018 Research-status Report
  • [Remarks] プレスリリース「J-PARCハドロン実験施設のKOTO実験が中性K中間子の稀な崩壊で...」

    • URL

      https://www2.kek.jp/ipns/ja/release/20190304/

    • Related Report
      2018 Research-status Report
  • [Remarks] [PRESS RELEASE] KOTO Experiment at ...

    • URL

      https://www2.kek.jp/ipns/en/release/20190304/

    • Related Report
      2018 Research-status Report
  • [Remarks] J-PARC News 第167号より「J-PARCハドロン実験施設の...」

    • URL

      http://j-parc.jp/ja/news/2019/news-j1903.html

    • Related Report
      2018 Research-status Report
  • [Remarks] 素粒子原子核研究所「4月の活動報告 : KOTO/Belle」

    • URL

      https://www2.kek.jp/ipns/ja/report/2017/04/

    • Related Report
      2017 Research-status Report
  • [Remarks] 素粒子原子核研究所「【特集】K中間子の稀な崩壊を探し、標準理論の限界に挑む 」

    • URL

      https://www2.kek.jp/ipns/ja/post/2017/10/koto-intro/

    • Related Report
      2017 Research-status Report
  • [Remarks] 素粒子原子核研究所「1月の活動報告 : KOTO実験グループ」

    • URL

      https://www2.kek.jp/ipns/ja/report/2018/01-1/

    • Related Report
      2017 Research-status Report
  • [Remarks] 素粒子原子核研究所「J-PARCハドロン実験施設へのビームパワーが50kWを超える」

    • URL

      https://www2.kek.jp/ipns/ja/post/2018/02/hadron50kw/

    • Related Report
      2017 Research-status Report
  • [Remarks] J-PARCセンター「J-PARC紹介映像(APS-TV)」

    • URL

      https://www.youtube.com/watch?v=6kXgS75ryqc&index=26&list=PLGVe6BxyFHNURBlEX9fPuE8VSBG9ilce-&t=0s

    • Related Report
      2017 Research-status Report

URL: 

Published: 2017-04-28   Modified: 2022-02-22  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi