Precision measurement of the orthopositronium decay rate using the vacuum technique

Two-Loop Correction to the Orthopositronium Decay Rate

“…The two most precise results are the 200 ppm Michigan gas [32,33] and vacuum [34] results of 1989 and 1990, which are in the latter group. Improved measurements by both the Tokyo [36] and the Michigan [39] groups are in the works, and the inconclusive experimental situation might soon be improved.…”

“…Subsequent theoretical refinements shifted the result only slightly. Since 1980, all measured results have fallen into two disjoint and mutually inconsistent groups: those clustered around the theoretical prediction of 7.040 µs −1 [31,35,36] and those near 7.050 µs −1 [30,[32][33][34].…”

Mirror matter in the solar system: new evidence for mirror matter from Eros

“…These implications depend importantly on the fundamental parameter which describes the strength of the photon-mirror photon interaction. We have decided to ignore interesting, but as yet unconfirmed hints suggesting ≈ 10 −6 [16] coming from the 1990 vacuum cavity orthopositronium experiment [17] and study how the physics changes as we vary (i.e. with 0 < < ∼ 10 −6 ).…”

“…The current experimental situation is summarized in Ref. [16], which shows that < ∼ 10 −6 , with some evidence for ≈ 10 −6 from the 1990 vacuum cavity experiment [17]. Photon-mirror photon kinetic mixing has other important implications, including astrophysical effects [18], the formation of ordinary atom-mirror atom bound states [19] and implications for early Universe cosmology [20].…”

Relativistic Corrections

“…The strong disagreement between the experimental value of the orthopositronium decay rate [1] Γ o−P s exp = 7.0482(16) µs −1 (1) and its theoretical value which includes the order α and α 2 log(1/α) corrections [2][3][4][5] Γ o−P s th = mα 6 2(π 2 − 9) 9π 1 − 10.28 α π − 1 3 α 2 log 1 α = 7.03830 µs −1 (2) is a real challenge to the modern QED. For the disagreement to be resolved within the QED framework, the correction ∼ (α/π) 2 , which has not been calculated completely up to now, should enter the theoretical result (2) with a numerical factor 250(40), which may look unreasonably large.…”