0 Order α 2 corrections to the decay rate of orthopositronium

Order α 2 corrections to the decay rate of orthopositronium are calculated in the framework of nonrelativistic QED. The resulting contribution is found to be in significant disagreement with one set of experimental measurements, though another experiment is in agreement with theory. The discrepancy between theory and experiment for the decay rate of orthopositronium has long been one of the outstanding problems in precision QED. The theory is given by Γ o−Ps = Γ 0 [1 + A α π + α 2 3 lnα + B(α π) 2 − 3α 3 2π ln 2 α] (1) where the lowest order decay rate is given by