====== TTP02-45 Five-loop vacuum polarization in pQCD: O(m_q^2\alpha_s^4 n_f^2) contribution ======
 
 
   <hidden TTP02-45  Five-loop vacuum polarization in pQCD: O(m_q^2\alpha_s^4 n_f^2) contribution > We present the analytical calculation of the contribution of order
 m_q^2 \alpha_s^4 n_f^2 to the absorptive part of the vacuum
 polarization function of vector currents. This term constitutes an
 important gauge-invariant part of the full O(m_q^2 alpha_s^4)
 correction to the total cross-section of e^+ e^- annihilation into
 hadrons.  The results are compared to predictions following from
 various optimization schemes.
 </hidden>
|**P.A. Baikov, K.G. Chetyrkin and J.H. K\"uhn**  | 
|**  Phys.Lett.B  559 245-251 2003  **  |
| {{preprints:2002:ttp02-45.pdf|PDF}} {{preprints:2002:ttp02-45.ps|PostScript}} [[http://arxiv.org/abs/hep-ph/0212303|arXiv]]   |
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