New Precise Measurement of the Hyperfine Splitting of Positronium
- Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
Positronium (Ps) is an ideal system for precision test of bound state quantum electrodynamics. The hyperfine splitting (HFS) of the ground state of Ps, which is one of the most precisely tested quantity, has a large discrepancy of 16 ppm (4.5 σ) between previous experiments and theoretical calculation up to O(α{sup 3}lnα{sup −1}) and part of O(α{sup 3}) corrections. A new experiment which reduces possible systematic uncertainties of Ps thermalization effect and nonuniformity of magnetic field was performed. It revealed that the Ps thermalization effect was as large as 10 ± 2 ppm. Treating the thermalization effect correctly, a new result of 203.3942 ± 0.0016(stat., 8.0 ppm) ± 0.0013(sys., 6.4 ppm) GHz was obtained. This result is consistent with theory within 1.1 σ, whereas it disfavors the previous experimental result by 2.6 σ. It shows that the Ps thermalization effect is crucial for precision measurement of HFS. Future prospects for improved precision are briefly discussed.
- OSTI ID:
- 22493965
- Journal Information:
- Journal of Physical and Chemical Reference Data, Vol. 44, Issue 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0047-2689
- Country of Publication:
- United States
- Language:
- English
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