Inclusive τ -Decay and QCD Sum Rules in Variational Perturbation Theory

Abstract

Nonperturbative expansion in quantum chromodynamics is applied to analyze low energy scale hadronic decay of τ -lepton data. Threshold singularities are summarized by a relativistic resummation S-factor. It is demonstrated that the suggested method allows good description of experimental D-function down to the lowest energy scale as well as parameters of ρ-meson.