Muon Decay Spectrum: Leading Logarithmic Approximation
  O(alpha^2 ln^2(m_mu/m_e)) QED corrections to the electron spectrum and angular distribution in muon decay are evaluated. Impact on the determination of Michel parameters is estimated. Current theoretical uncertainty in the muon decay distributions is discussed. 
Andrej Arbuzov, Andrzej Czarnecki, Andrei Gaponenko (Alberta U.)