====== TTP04-29 Vacuum polarization in pQCD: first complete O(\alpha_s^4) result ======
 
 
<hidden TTP04-29  Vacuum polarization in pQCD: first complete O(\alpha_s^4) result > We report  the results of the   first complete QCD five-loop
 calculation, viz. analytical contribution of order m_q^2 alpha_s^4,
 to the (absorptive part of) the vacuum polarization function. The
 contribution directly leads to the knowledge of the the 
 full O( \als^4  m_q^2/ s)correction to the total cross-section
 of e^+ e^- annihilation into hadrons. We  compare
 our results with predictions following from various optimization
 schemes.
 </hidden>
|**P.A. Baikov, K.G. Chetyrkin and  J.H.K\"uhn**  | 
|**  Nucl. Phys. Proc. Suppl.  135 243-246 2004  **  |
| {{preprints:2004:ttp04-29.pdf|PDF}} {{preprints:2004:ttp04-29.ps|PostScript}}   |
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