New Measurement of the Positronium Hyperfine Interval

Abstract

tions due to the self-energy, vacuum polarization, magnetic interaction, and retardation. Nearly all of these corrections have been calculated by expansions in terms of the parameter Za, but experiments are already being conducted in the region where Za > 1. This is a great challenge to the theory. An approach to ab initio relativistic many-electron molecular Hartree-Fock calculations is under way.

Positronium hyperfine splitting at ordermα7: Light-by-light scattering in the two-photon-exchange channel

“…Also in the seventies, Mills and Bearman [13,14] performed a measurement with similar precision: ∆E = 203 387.5(1.6)M Hz (7.9 ppm).…”

Hard three-loop corrections to hyperfine splitting in positronium and muonium

“…The hyperfine splitting in positronium is measured with the error bars at the level of 1-2 MHz [13][14][15][16]. There is a discrepancy about three standard deviations between the results of old and new experiments.…”

New Precision Measurement of Hyperfine Splitting of Positronium

“…The timing information between Ps formation and decay is newly obtained in this experiment to investigate the nonthermalized Ps effect. The basic idea of the other setup is the same as the previous experiments [27,28,29,3,30,31,4,5].…”

“…The ground state hyperfine splitting between o-Ps and p-Ps (Ps-HFS, ∆ HFS ) is an ideal probe for the precise test of the bound-state QED. The combined value of the two most precise experiments is ∆ exp HFS = 203.388 65(67) GHz(3.3 ppm) [3,4,5]. Recent developments in non-relativistic QED (NRQED) have added O(α 3 ln α −1 ) corrections to the theoretical prediction which now stands at ∆ th HFS = 203.391 69(41) GHz(2.0 ppm) [6,7,8].…”