Abstract

Measurements of the differential cross sections for e+e−→μ+μ− and e+e−→τ+τ− at values of s from 52 to 57 GeV are reported. The forward-backward asymmetries and the total cross sections for these reactions are found to be in agreement with predictions of the standard model of the electro-weak interactions. These measurements are used to extract values of the weak coupling constant gvegvl and gAegAl, where l = μ or τ.