====== TTP96-04 DOUBLE BUBBLE CORRECTIONS TO HEAVY QUARK PRODUCTION ======
 
 
   <hidden TTP96-04  DOUBLE BUBBLE CORRECTIONS TO HEAVY QUARK PRODUCTION > Second order ${\cal O}(\alpha_s^2)$ corrections to the heavy quark 
 production cross-section due to massless quarks and coloured scalars  
 are calculated for all energies above threshold. Based on the method
 introduced in this letter also the gauge non-invariant second order
 corrections due to the pure gluonic self-energy insertion and a certain
 class of ${\cal{O}}(\alpha_s^3)$ and
 ${\cal{O}}(\alpha_s^4)$ corrections are
 determined. For the special choice of the gauge parameter, $\xi=4$, the
 leading threshold and high energy behaviour of the pure second order
 gluonic corrections to the cross-section are governed by the
 gluonic self-energy insertion. 
 </hidden>
|**K.G. Chetyrkin, A.H. Hoang, J.H. Kuehn, M. Steinhauser, T. Teubner**  | 
|** Phys. Lett. B 384 233-240 1996  **  |
| {{preprints:1996:ttp96-04.pdf|PDF}} {{preprints:1996:ttp96-04.ps|PostScript}} [[http://arxiv.org/abs/hep-ph/9603313|arXiv]]   |
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