====== TTP04-28 Strange Quark Mass from Tau Lepton Decays with O(\alpha_s^3) Accuracy ======
 
 
   <hidden TTP04-28  Strange Quark Mass from Tau Lepton Decays with O(\alpha_s^3) Accuracy > The first complete calculation of the quadratic quark mass correction
 to the correlator of the two currents relevant for the
 strangeness-changing semihadronic tau-decay rate is presented 
 including its real part at the four-loop level.  This allows to
 perform the extraction of the strange quark mass m_s from the decay
 width of the tau-lepton with  full  O(alpha_s^3)
 accuracy.  In agreement with previous estimates the newly computed
 alpha_s^3 term proves to be rather large. This justifies inclusion
 of the similarly estimated alpha_s^4 term in phenomenological
 analysis. Combined with an updated value of V_{us} and an
 ``'improved'' version of the renormalization group improvement of the
 perturbative series this leads to an increase of the central value of
 m_s by about 20% and a partial reduction of the theoretical
 uncertainty by about 50%. 
 </hidden>
|**P.A. Baikov, K.G. Chetyrkin and  J.H.K\"uhn**  | 
|**  Phys. Rev. Lett.  95 012003-1 2005  **  |
| {{preprints:2004:ttp04-28.pdf|PDF}} {{preprints:2004:ttp04-28.ps|PostScript}} [[http://arxiv.org/abs/hep-ph/0412350|arXiv]]   |
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