O(ALPHA-2IN(ALPHA-1)) CORRECTIONS IN POSITRONIUM - HYPERFINE SPLITTING AND DECAY-RATE

The authors have analyzed the terms of relative order 2ln(-1) that come from annihilation kernels in positronium, and have found a contribution of 6ln(-1)me24 to positronium hyperfine splitting from annihilation kernels, including several new contributions. The resulting hyperfine splitting is 203.4003 GHz, with terms of order 6me20.01 GHz uncomputed. The contributions to the decay rates of ortho- and parapositronium have also been calculated. For orthopositronium the result is -2ln(-1)03. The authors present in more detail the theoretical analysis leading to their previous 0 calculation and improve on the numerical results. The resulting theoretical orthopositronium decay rate is 7.03860.0002 sec-1, with terms of order 20=0.0004 sec-1 uncalculated. © 1979 The American Physical Society.