Long-distance radiative corrections to the di-pion tau lepton decay
  We evaluate the model-dependent piece of O(alpha) long-distance radiative corrections to tau^- \to \pi^- \pi^0\nu_{\tau} decays by using a meson dominance model. We find that these corrections to the di-pion invariant mass spectrum are smaller than in previous calculations based on chiral perturbation theory. The corresponding correction to the photon inclusive rate is tiny (-0.15%) but it can be of relevance when new measurements reach better precision. 
F. Flores-Baez, A. Flores-Tlalpa, G. Lopez Castro and G. Toledo   Sanchez