New precise spectroscopy of the hyperfine structure in muonium with a high-intensity pulsed muon beam

S. Kanda, Y. Fukao, Y. Ikedo, K. Ishida, M. Iwasaki, D. Kawall, N. Kawamura, K. M. Kojima, N. Kurosawa, Y. Matsuda, T. Mibe, Y. Miyake, S. Nishimura, N. Saito, Y. Sato, S. Seo, K. Shimomura, P. Strasser, K. S. Tanaka, T. TanakaH. A. Torii, A. Toyoda, Y. Ueno

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


A hydrogen-like atom consisting of a positive muon and an electron is known as muonium. It is a near-ideal two-body system for a precision test of bound-state theory and fundamental symmetries. The MuSEUM collaboration performed a new precision measurement of the muonium ground-state hyperfine structure at J-PARC using a high-intensity pulsed muon beam and a high-rate capable positron counter. The resonance of hyperfine transition was successfully observed at a near-zero magnetic field, and the muonium hyperfine structure interval of νHFS=4.463302(4)GHz was obtained with a relative precision of 0.9 ppm. The result was consistent with the previous ones obtained at Los Alamos National Laboratory and the current theoretical calculation. We present a demonstration of the microwave spectroscopy of muonium for future experiments to achieve the highest precision.

Original languageEnglish
Article number136154
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Publication statusPublished - 2021 Apr 10
Externally publishedYes


  • High-intensity pulsed beam
  • Hyperfine structure (HFS)
  • Muon
  • Muonium
  • Quantum electrodynamics (QED)

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


Dive into the research topics of 'New precise spectroscopy of the hyperfine structure in muonium with a high-intensity pulsed muon beam'. Together they form a unique fingerprint.

Cite this