Direct Measurement of Positronium Hyperfine Splitting in Vacuum

• Project/Area Number: 23740173
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: The University of Tokyo
• Principal Investigator: SUEHARA Taikan 東京大学, 素粒子物理国際研究センター, 特任研究員 (20508387)
• Project Period (FY): 2011 – 2012
• Project Status: Completed (Fiscal Year 2012)
• Budget Amount: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000); Fiscal Year 2012: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2011: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
• Keywords: ポジトロニウム / 超微細構造 / テラヘルツ / ジャイロトロン / 共振器 / グレーティング

Research Abstract

We observed the direct transition between ortho-positronium and para-positronium using 203 GHz high power radiation to measure the hyperfine splitting of positronium. With a high power radiation source, gyrotron, and a Fabry-Perot cavity with golden mesh mirror on a high-resistivity silicon, we succeeded to observe the transition of more than 10 sigma significance. We also measured the transition curve with measurements using radiation of multiple frequencies.

Research Products

• [Journal Article] Direct Observation of the Hyperfine Transition of Ground-State Positronium (2012)
  • Author(s): Akira Miyazaki, (10名中2人目)
  • Journal Title: Physical Review Letters Volume: 108 Issue: 25 Pages: 253401-253401
  • DOI: 10.1103/physrevlett.108.253401
  • Peer Reviewed
• [Journal Article] The First Direct Observation of Positronium Hyperfine Splitting (2012)
  • Author(s): T. Suehara, T. Yamazaki, A. Miyazaki, G. Akimoto, A. Ishida, T. Namba, S. Asai, T. Kobayashi, H. Saito, T. Idehara, I. Ogawa, S. Sabchevski
  • Journal Title: AIP Conference Proceedings Volume: 1441 Pages: 549-551
  • DOI: 10.1063/1.3700613
  • Peer Reviewed
• [Journal Article] First observation of o-Ps to p-Ps transition and first direct measurement of positronium hyperfine splitting with sub-THz light (2011)
  • Author(s): T.Yamazaki, A.Miyazaki, T.Suehara, T.Namba, S.Asai, T.Kobayashi, H.Saito, Y.Urushizaki, I.Ogawa, T.Idehara, S.Sabchevski
  • Journal Title: Hyperfine Interaction Volume: (online first) Issue: 1-3 Pages: 141-147
  • DOI: 10.1007/s10751-011-0399-0
  • Peer Reviewed
• [Journal Article] (2010)
  • Author(s): A. Miyazaki、T. Yamazaki、T. Suehara、 T. Namba、S. Asai、T. Kobayashi, H. Saito、T. Idehara、I. Ogawa、S. Sabchevski
  • Journal Title: Materials Science Forum Volume: 666巻 Pages: 133-137
  • DOI: 10.4028/www.scientific.net/msf.666.133
  • Peer Reviewed
• [Presentation] Direct Measurement of the Hyperfine Transition of Positronium using High Power Sub-THz Radiation (2013)
  • Author(s): 山崎高幸
  • Organizer: 日本物理学会第 68回年次大会
  • Place of Presentation: 広島大学(広島県)(招待講演)
  • Year and Date: 2013-03-28
• [Presentation] Direct Measurement of the Hyperfine Transition of Positronium using High Power Sub-THz Radiation (2013)
  • Author(s): 山崎 高幸
  • Organizer: 日本物理学会第68回年次大会
  • Place of Presentation: 広島大学 （広島県）
  • Invited
• [Presentation] The direct spectroscopy of positronium hyperfine structure using sub-THz gyrotron (2012)
  • Author(s): Akira Miyazaki
  • Organizer: International Symposium on Frontiers in THz Technology
  • Place of Presentation: Todaiji Culture Center (Japan)(招待講演)
  • Year and Date: 2012-11-27
• [Presentation] Direct measurement of the Hyperfine Structure of the Groundstate Positronium using High Power sub-THz radiation (2012)
  • Author(s): Takayuki Yamazaki
  • Organizer: The 37th International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz)
  • Place of Presentation: Wollongong (Australia)
  • Year and Date: 2012-09-28
• [Presentation] The First Direct Observation of Positronium Hyperfine Splitting (Ps-HFS) (2012)
  • Author(s): Taikan Suehara
  • Organizer: The 19th Particles and Nuclei International Conference
  • Place of Presentation: Boston (USA)
  • Year and Date: 2012-07-25
• [Presentation] Direct Measurement of the Hyperfine Structure of the Ground State Positronium using High Power Sub-THz Radiation (2012)
  • Author(s): Takayuki Yamazaki
  • Organizer: 37th International Conference on Infrared, Millimeter and Terahertz Waves
  • Place of Presentation: University of Wollongong, Australia
• [Presentation] The direct spectroscopy of positronium hyperfine structure using sub-THz gyrotron (2012)
  • Author(s): Akira Miyazaki
  • Organizer: International Symposium on Frontiers in THz Technology
  • Place of Presentation: Todaiji Culture Center, Japan
  • Invited
• [Presentation] The first observation of direct transition between o-Ps and p-Ps by sub-THz radiation (2011)
  • Author(s): Taikan Suehara
  • Organizer: Cold Antimatter and High Precision Physics (Pbar11)招待講演
  • Place of Presentation: Matsue (Japan)
  • Year and Date: 2011-11-29
• [Presentation] The First Direct Observation of Positronium Hyperfine Splitting (Ps-HFS) (2011)
  • Author(s): Taikan Suehara
  • Organizer: The 19th Particles and Nuclei International Conference (PANIC11)
  • Place of Presentation: Boston, USA
• [Presentation] The first observation of direct transition between o-Ps and p-Ps by sub-THz radiation (2011)
  • Author(s): Taikan Suehara
  • Organizer: Cold Antimatter and High Precision Physics (Pbar11)(招待講演)
  • Place of Presentation: Matsue, Japan
• [Remarks]
  • URL: http://tabletop.icepp.s.u-tokyo.ac.jp/Tabletop_experiments/Direct_HFS_measurement.html
• [Remarks] サブテラヘルツ波を用いたポジトロニウム超微細構造の直接測定
  • URL: http://tabletop.icepp.s.u-tokyo.ac.jp/Tabletop_experiments/Direct_HFS_measurement.html
• [Remarks]
  • URL: http://tabletop.icepp.s.u-tokyo.ac.jp/