First millimeter-wave spectroscopy of ground-state positronium

A. Miyazaki, T. Yamazaki, T. Suehara, T. Namba, S. Asai, T. Kobayashi, H. Saito, Y. Tatematsu, I. Ogawa, T. Idehara

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


We report on the first measurement of the Breit-Wigner resonance of the transition from ortho-positronium to para-positronium. We have developed an optical system to accumulate a power of over 20 kW using a frequency-tunable gyrotron and a Fabry-Pérot cavity. This system opens a new era of millimeter-wave spectroscopy, and enables us to directly determine both the hyperfine interval and the decay width of para-Ps.

Original languageEnglish
Article number011C01
JournalProgress of Theoretical and Experimental Physics
Issue number1
Publication statusPublished - Oct 10 2014

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)


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