====== TTP97-18 Heavy Quark Current Correlators to ${\cal O}(\alpha_s^2)$  ======
 
 
   <hidden TTP97-18  Heavy Quark Current Correlators to ${\cal O}(\alpha_s^2)$  > In this paper the three-loop polarization functions \Pi(q^2)
 are calculated for the cases of an external vector, axial-vector, scalar or
 pseudo-scalar current. Results are presented for the
 imaginary part which directly leads to the cross section
 $\sigma(e^+e^- \to Z \to hadrons)$ and to the Higgs
 decay rates, respectively.
 
 </hidden>
|**K.G. Chetyrkin, J.H. Kuehn, M. Steinhauser**  | 
|** Nucl. Phys. B505 40-64 1997  **  |
| {{preprints:1997:ttp97-18.pdf|PDF}} {{preprints:1997:ttp97-18.ps|PostScript}} [[http://arxiv.org/abs/hep-ph/9705254|arXiv]]   |
| |