Electromagnetic properties of the neutrinos and the pion radiative decay

We investigate the implications of neutrino electromagnetic dipole moments for the radiative decay $\pi \rightarrow e \nu \gamma$. We show that the dominant new effect comes from the interference between the amplitude of the process with the photon emitted by the neutrino and the structure dependent standard amplitude. Such interference takes place only if the massive neutrino is a Majorana fermion. Moreover, since electric and magnetic dipole moments give rise to contributions with opposite signs, future experiments might be able to distinguish between them.