Model-independent approach to eta -> pi+ pi- gamma and eta' -> pi+ pi-   gamma
  We present a new, model-independent method to analyze radiative decays of mesons to a vector, isovector pair of pions of invariant mass square below the first significant pion-pion threshold in the vector channel. It is based on a combination of chiral perturbation theory and dispersion theory. This allows for a controlled inclusion of resonance physics without the necessity to involve vector meson dominance explicitly. As an example, the method is applied to an analysis of the reactions eta -> pi+ pi- gamma and eta'->pi+ pi- gamma. 
F. Stollenwerk, C. Hanhart, A. Kupsc, U.-G. Mei{\ss}ner, A. Wirzba
nucl-th hep-ph