====== TTP07-11 Title : Ultrasoft contribution to quarkonium production and annihilation ======
 
 
   <hidden TTP07-11  Title : Ultrasoft contribution to quarkonium production and annihilation > We compute the third-order correction to electromagnetic 
 S-wave quarkonium production and annihilation rates due to the emission and absorption of an ultrasoft gluon. Our result completes the analysis of the non-relativistic quarkonium bound-state dynamics in the next-to-next-to-next-to-leading order. The impact of the ultrasoft correction on the Upsilon(1S) leptonic width and the top quark-antiquark threshold production cross section is estimated. 
 </hidden>
|**M. Beneke, Y. Kiyo and A. A.Penin**  | 
|**  Phys.Lett.  B653 53-56 2007  **  |
| {{preprints:2007:ttp07-11.pdf|PDF}} {{preprints:2007:ttp07-11.ps|PostScript}} [[http://arxiv.org/abs/0706.2733|arXiv]]   |
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