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   Delta Gamma_had = -Gamma_0(alpha/pi)^2(0.042)   where Gamma_0 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   Delta Gamma_muon   = Gamma_0(alpha/pi)^2[(16987/576)-(85/36)zeta(2)-(64/3)zeta(3)]   = -Gamma_0(alpha/pi)^2(0.0364333)   Delta Gamma_tau = -Gamma_0(alpha/pi)^2)(0.00058) 
Timo van Ritbergen and Robin G. Stuart (Randall Laboratory of Physics)