20-27 July 2011
Alpes Congrès - Alpexpo
Europe/Paris timezone

Singlet Contribution to the Vector Correlator

22 Jul 2011, 15:45
Bayard (Alpes Congrès - Alpexpo)


Alpes Congrès - Alpexpo

Parallel session talk QCD QCD


Johann Kuehn (KIT)


We compute, for the first time, the order alpha_s^4 contribution to the singlet Adler function for the case of a genereric colour gauge group. Giving access to the terms proportional to the squared sum of the quark charges, this result completes the alpha_s^4 corrections to the familiar R-ratio as measured in electron-positron annihilation. Adopting the colour factors to the U(1) group, the full five-loop QED beta-function is completed. An independent calculation leads to the singlet contribution of order alpha_s^4 to the Gross-Llewellyn Smith sum rule. Relating Adler function and sum rule through the generalized Crewther relation leads to two non-trivial constrains which are indeed fullfilled. This cross check gives additional confidence in the correctness of this highly complicated calculation.

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