The tau+ tau- production cross section near threshold revisited

Abstract

Next-to-next-to-leading contributions to the cross section sigma(e+e- -> tau+tau-) at energies close to threshold are analysed, taking into account the known non-relativistic effects and O(alpha^2) corrections. The numerical changes with respect to previous works are small, but the new corrections give a true estimate of the uncertainty in the theoretical calculation.

Comments: Invited talk at the Seventh International Workshop on Tau Lepton Physics (TAU02), Santa Cruz, Ca, USA, Sept 2002, 5 pages, LaTeX, 5 ps figures, PSN Tau02-TU01