On the Radiative Pion Decay
  A reanalysis of the radiative pion decay together with the calculation of the radiative corrections within chiral perturbation theory (CHPT) is performed. The amplitude of this decay contains an inner Bremsstrahlung contribution and a structure-dependent part that are both accessible in experiments. In order to obtain a reliable estimate of the hadronic contributions we combine the CHPT result with a large-N_C expansion and experimental data on other decays, which makes it possible to determine the occurring coupling constants. 
Rene Unterdorfer, Hannes Pichl