NNLO tau+tau- production cross section at threshold
  The threshold behaviour of the cross section sigma(e+e- -> tau+tau-) is analysed, taking into account the known higher-order corrections. At present, this observable can be determined to next-to-next-to-leading order (NNLO) in a combined expansion in powers of alpha_s and fermion velocities. 
P. Ruiz-Femenia and A. Pich (IFIC-Universidad de Valencia, Valencia)