Hadronic contributions to the muon lifetime

Hadronic corrections to the muon lifetime are calculated in the Fermi theory in the presence of QED using dispersion relations. The result, after convolution of hadron data with the calculated perturbative kernel is ΔΓhad=−Γ0απ20.042 where Γ0 is the tree-level width. The results are also used to obtain the corrections to the muon lifetime coming from virtual muon and tau loops ΔΓmuon=Γ0απ216987576−8536ζ(2)−643ζ(3)=−Γ0απ20.0364333 , ΔΓtau=−Γ0απ20.00058.