====== TTP99-20 alpha^2 corrections to parapositronium decay ======
 
 
   <hidden TTP99-20  alpha^2 corrections to parapositronium decay > Two-loop QED corrections to the decay rate of parapositronium (p-Ps)
 into two photons are presented.  We find Gamma(p-Ps --> 2 photons) =
 7989.50(2)/microsec.  The non-logarithmic O(alpha^2) corrections turn
 out to be small, contrary to some earlier estimates. We speculate that
 the so-called ``orthopositronium lifetime puzzle'' will not likely be
 solved by large QED corrections.
 </hidden>
|**A. Czarnecki, K. Melnikov and A. Yelkhovsky**  | 
|**  Phys. Rev. Lett.  83 1135-1138 1999  **  |
| {{preprints:1999:ttp99-20.pdf|PDF}} {{preprints:1999:ttp99-20.ps|PostScript}} [[http://arxiv.org/abs/hep-ph/9904478|arXiv]]   |
| |