2013/10/31 by A. Ishida, Akira Ishida, T. Namba +8 · 4 citations
Engineering · Physics and Astronomy · #Atomic and Molecular Physics #Atomic physics #Electron #Ground state #Hyperfine structure #Muon and positron interactions and applications #Particle physics theoretical and experimental studies #Physics #Positron #Positronium #Quantum electrodynamics #Quantum mechanics #Thermalisation #hep-ex #physics.atom-ph
paper · pdf · doi:10.1016/j.physletb.2014.05.083
published as Phys. Lett. B 734 (2014) 338-344 · 8 pages, 10 figures, accepted by Physics Letters B
arxiv created 2014/05/30 · openalex publication_date 2014/06/01 · arxiv updated 2014/06/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The ground state hyperfine splitting of positronium ΔHFS is sensitive to high order corrections of quantum electrodynamics (QED) in bound state. The theoretical prediction and the averaged experimental value for ΔHFS have a discrepancy of 15 ppm, which is equivalent to 3.9 standard deviations (s.d.). A new precision measurement which reduces the systematic uncertainty from the positronium thermalization effect was performed, in which the non-thermalization effect was measured to be as large as 10±2ppm in a timing window we used. When this effect is taken into account, our new result becomes ΔHFS=203.3942±0.0016(stat.,8.0ppm)±0.0013(sys.,6.4ppm)GHz, which favors the QED prediction within 1.2 s.d. and disfavors the previous experimental average by 2.6 s.d.