$a \to e^+ e^-$ decay in a model with induced coupling to leptons
  The process of electron-positron pair production by axion propagating in an external magnetic field is investigated in a model with only induced axion coupling to leptons. Contributions of the lowest and higher Landau levels are analyzed. The results we have obtained demonstrate a strong catalyzing influence of the field. 
N.V. Mikheev, O.S. Ovchinnikov and L.A. Vassilevskaya