Precise measurement of positronium hyperfine splitting using the Zeeman effect

Akira Ishida, Yuichi Sasaki, Ginga Akimoto, Taikan Suehara, Toshio Namba, Shoji Asai, Tomio Kobayashi, Haruo Saito, Mitsuhiro Yoshida, Kenichi Tanaka, Akira Yamamoto

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Positronium is an ideal system for the research of the quantum electrodynamics (QED) in bound state. The hyperfine splitting (HFS) of positronium, Δ HFS, gives a good test of the bound state calculations and probes new physics beyond the Standard Model. A new method of QED calculations has revealed the discrepancy by 15 ppm (3.9σ) of Δ HFS between the QED prediction and the experimental average. There would be possibility of new physics or common systematic uncertainties in the previous all experiments. We describe a new experiment to reduce possible systematic uncertainties and will provide an independent check of the discrepancy. We are now taking data and the current result of Δ HFS = 203.395 1 ±0.002 4 (stat., 12 ppm) ±0.001 9 (sys., 9. 5 ppm) GHz has been obtained so far. A measurement with a precision of O(ppm) is expected within a year.

Original languageEnglish
Pages (from-to)133-140
Number of pages8
JournalHyperfine Interactions
Issue number1-3
Publication statusPublished - Dec 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Nuclear and High Energy Physics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


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