2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/213729The 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.4 pages, 3 figures. To appear in the proceedings of QCD 02: High-Energy Physics International Conference in Quantum Chromodynamics, Montpellier, France, 2-9 Jul 2002High Energy Physics - Phenomenologytext