A Precision Measurement of the Branching Ratio in Pion Decay and Search for the Physics beyond the Standard Model

• Project/Area Number: 21340059
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Osaka University
• Principal Investigator: AOKI Masaharu 大阪大学, 理学研究科, 准教授 (80290849)
• Co-Investigator(Kenkyū-buntansha): YOSHIDA Makoto 高エネルギー加速器研究機構, 素粒子原子核研究所, 助教 (70379303)
• Co-Investigator(Renkei-kenkyūsha): IGARASHI Youichi 高エネルギー加速器研究機構, 素粒子原子核研究所, 助教 (50311121) ; KOMATSUBARA Takeshi 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)
• Research Collaborator: BRYMAN Douglas University of British Columbia (Canada), Professor ; NUMAO Toshio TRIUMF (Canada), 上級研究員 ; ITOU Shintaro 大阪大学, 大学院・理学研究科, 博士前期大学院生 ; ITOU Naosuke 大阪大学, 大学院・理学研究科, 博士前期大学院生 ; YAMADA Kaoru 大阪大学, 大学院・理学研究科, 博士前期大学院生
• Project Period (FY): 2009 – 2012
• Project Status: Completed (Fiscal Year 2012)
• Budget Amount: ¥18,850,000 (Direct Cost: ¥14,500,000、Indirect Cost: ¥4,350,000); Fiscal Year 2011: ¥5,590,000 (Direct Cost: ¥4,300,000、Indirect Cost: ¥1,290,000); Fiscal Year 2010: ¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000); Fiscal Year 2009: ¥6,760,000 (Direct Cost: ¥5,200,000、Indirect Cost: ¥1,560,000)
• Keywords: 素粒子(実験) / 精密測定 / レプトン普遍性 / 荷電ヒッグス / パイオン / CLFV / 標準理論 / 荷電レプトン・フレーバ非保存 / 波形記録

Research Abstract

An experiment to search for new physics beyond the Standard Model of particle physics by measuring the branching ratio of pion decays was performed. Adetector which was built with a large NaI(Tl) single crystal was installed at M13 beam line at TRIUMF, and a physics data taking was performed. A physics analysis with 10% of whole data set was performed, and it is confirmed that the final sensitivity with whole data set will be better than 0.1% in relative error. The physics analysis is expected to take more time since a blind analysis policy is adopted. New upper limits on massive neutrinos were obtained.

Research Products

• [Journal Article] Measurement of the pion branching ratio at TRIUMF (2012)
  • Author(s): C. Malbrunot, M. Aoki, Y. Igarashi, M. Yoshida
  • Journal Title: AIP Conf. Proc. Volume: 1441巻 Pages: 564-566
• [Journal Article] The PIENU experiment at TRIUMF: A sensitive probe for new physics (2011)
  • Author(s): C. Malbrunot, M. Aoki, Y. Igarashi, M. Yoshida
  • Journal Title: J. Phys. Conf. Ser. Volume: 312巻
• [Journal Article] Search for massive neutrinos in the decay π→eν (2011)
  • Author(s): M. Aoki, Y. Igarashi,M. Yoshida 他19名
  • Journal Title: Phys. Rev. D Volume: 84巻
  • Peer Reviewed
• [Journal Article] Search for massive neutrinos in the decay (2011)
  • Author(s): M. Aoki, M. Blecher, その他
  • Journal Title: Physical Review D Volume: 84 Issue: 5 Pages: 52002-52002
  • DOI: 10.1103/physrevd.84.052002
  • Peer Reviewed
• [Journal Article] Measurement of the pion branching ratio at TRIUMK (2011)
  • Author(s): C. Malbrunot, M. Aoki, その他.
  • Journal Title: AIP Conference Proceedings Volume: 1441 Pages: 564-566
  • DOI: 10.1063/1.3700618
• [Journal Article] An experimental search for muon-electron conversion in nuclear field atsensitivity of 10-14 with a pulsed proton beam (2011)
  • Author(s): M. Aoki, その他
  • Journal Title: AIP Conference Proceedings Volume: 1441 Pages: 599-601
  • DOI: 10.1063/1.3700628
• [Journal Article] Study of a large NaI(Tl) crystal (2010)
  • Author(s): A. Aguilar-Arevalo, M. Aoki, M. Blecher
  • Journal Title: Nucl. Instrum. Methods Phys. Res., Sect. A Volume: 621巻 Pages: 188-191
  • Peer Reviewed
• [Journal Article] Study of a large NaI(T1) crystal (2010)
  • Author(s): A.Aguilar-Arevalo, M.Aoki, その他
  • Journal Title: Nucl.Instrum.and Methods, Phys.Res.A Volume: 621 Pages: 188-191
  • Peer Reviewed
• [Presentation] その他PIENU Collaboration, π+→e+νe 崩壊分岐比の精密測定における時間スペクトラム解析 -PIENU- (2013)
  • Author(s): 伊藤慎太郎,青木正治,五十嵐洋一,久野良孝
  • Organizer: 日本物理学会
  • Place of Presentation: 広島大学
  • Year and Date: 2013-03-29
• [Presentation] The new pi-e-nu experiments,招待講演 (2011)
  • Author(s): M. Aoki
  • Organizer: the 13th Annual Meeting of the Northwest Section of the American Physical Society
  • Place of Presentation: Corvallis USA
  • Year and Date: 2011-10-21
• [Presentation] レプトンユニバーサリティの破れの探索 (2011)
  • Author(s): 青木正治
  • Organizer: 日本物理学会
  • Place of Presentation: 弘前大学
  • Year and Date: 2011-09-18
• [Presentation] The new pi-e-nu experiments (2011)
  • Author(s): M. Aoki
  • Organizer: The 13th Annual Meeting of the Northwest Section of the American Physical Society
  • Place of Presentation: Corvallis,米国(招待講演)
• [Presentation] An Experimental Search for Muon-Electron Conversion in Nuclear Fieldat Sensitivity of 10・14 with Pulsed Protong Beam -DeeMe (2011)
  • Author(s): M. Aoki, その他
  • Organizer: Fundamental Physics at the Intensity Frontier
  • Place of Presentation: Rockville,米国
• [Presentation] -DeeMe- An Experimental Search for μ-e Conversion in Nuclear Meld at Sensitivity of io-14 with Pulsed Proton Beam from J-PARC RCS (2011)
  • Author(s): M. Aoki, その他
  • Organizer: US-Japan Workshop
  • Place of Presentation: つくば,日本
• [Presentation] Rare Decays (2010)
  • Author(s): Masaharu Aoki
  • Organizer: Precision Tests of the Standard Model from Atomic Parity Violation to Parity-Violating Lepton Scattering
  • Place of Presentation: ECT*, Trento (Italy)(招待講演)
  • Year and Date: 2010-11-11
• [Presentation] Rare Decays, 招待講演 (2010)
  • Author(s): M. Aoki
  • Organizer: Precision Tests of the Standard Model
  • Place of Presentation: ECT* Trento Italy
  • Year and Date: 2010-11-10
• [Presentation] π^+→e^+ν_e崩壊分岐比測定実験-実験開始- (2009)
  • Author(s): 山田薫
  • Organizer: 日本物理学会2009年秋期大会
  • Place of Presentation: 甲南大学(兵庫)
  • Year and Date: 2009-09-10
• [Book] Search for Massive Neutrinos in π^+→e^+ν_e Decay (2010)
  • Author(s): 山田薫
  • Total Pages: 125
  • Publisher: 自費出版(博士号論文)