====== TTP01-21 Determination of $\alpha_s$ and heavy quark masses  from recent measurements of $R(s)$ ======
 
 
   <hidden TTP01-21  Determination of $\alpha_s$ and heavy quark masses  from recent measurements of $R(s)$ > In this paper we compare recent experimental data for the total cross
 section $\sigma(e^+e^-\to\mbox{hadrons})$ with the up-to-date
 theoretical prediction of perturbative QCD for those energies where
 perturbation theory is reliable. The excellent agreement suggests the
 determination of the strong coupling $\alpha_s$ from the measurements
 in the continuum. The precise data from the charm threshold region,
 when combined with the recent evaluation of moments with three loop
 accurracy, lead to a direct determination of the short distance
 $\overline{\rm MS}$ charm quark mass. Our result for the strong
 coupling constant $\alpha_s^{(4)}(5~\mbox{GeV})=0.235^{+0.047}_{-0.047}$  
 corresponds to $\alpha_s^{(5)}(M_Z)=0.124^{+0.011}_{-0.014}$, 
 for the charmed quark mass we find $m_c(m_c)=1.304(27)$. Applying the
 same approach to the bottom quark we obtain $m_b(m_b)=4.191(51)$~GeV. 
 Whereas our result for $\alpha_s(M_Z)$ serves as a useful cross
 check for other more precise determinations, our values for the charm
 and bottom quark masses are more accurate than other recent analyses. 
 </hidden>
|**J.H. K\"uhn and M. Steinhauser**  | 
| {{preprints:2001:ttp01-21.pdf|PDF}} {{preprints:2001:ttp01-21.ps|PostScript}} [[http://arxiv.org/abs/hep-ph/0109084|arXiv]]   |
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