Two-Loop Correction to the Orthopositronium Decay Rate

✍ Scribed by Gregory S. Adkins; Richard N. Fell; J. Sapirstein

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 473 KB
• Volume: 295
• Category: Article
• ISSN: 0003-4916
• DOI: 10.1006/aphy.2001.6219

✦ Synopsis

We give a detailed description of our calculation of the O(α 2 ) correction to the orthopositronium decay rate. The resulting correction is 45.06(26) in units of (α/π) 2 times the lowest order rate. When combined with other known corrections, the theoretical prediction for the decay rate is 7.039979(11) µs -1 , where the leading uncalculated term makes an estimated contribution of roughly 0.00002 µs -1 . Our result is in significant disagreement with two of the four highest precision measurements (at about the 5σ level), but does not contradict the others. The experimental uncertainties (≈0.002 µs -1 ) are much larger than the remaining theoretical uncertainties. We also calculate the one-photon-annihilation contribution to the positronium hyperfine structure at O(mα 6 ). This calculation is closely analogous to the decay rate calculation. Our agreement with prior results for this hyperfine structure contribution demonstrates the soundness of our approach.