The Dalitz decay π0 → e+e-γ revisited

The amplitude of the Dalitz decay pi(0) -> e(+)e(-)gamma is studied and its model-independent properties are discussed in detail. A calculation of radiative corrections is performed within the framework of two-flavor chiral perturbation theory, enlarged by virtual photons and leptons. The lowest meson dominance approximation, motivated by large N-C considerations, is used for the description of the pi(0)-gamma*-gamma* transition form factor and for the estimate of the NLO low energy constants involved in the analysis. The two photon reducible contributions are included and discussed. Previous calculations are extended to the whole kinematical range of the soft photon approximation, thus allowing for the possibility to consider various experimental situations and observables.