R(s) and Z decay in order \alpha_s^4: complete results
  We report on our calculation of the order \alpha_s^4 axial singlet contributions for the decay rates of the Z-boson as well as the vector singlet contribution to the cross section for electron-positron annihilation into hadrons. Together with recently finished O(\alpha_s^4) calculations of the non-signlet corrections [1,2], the new results directly lead us to the first complete O(\alpha_s^4) predictions for the total hadronic decay rate of the Z-boson and the ratio R(s). 
P. A. Baikov, K. G. Chetyrkin, J. H. K\"uhn and J. Rittinger
hep-ph