  In frame of a phenomenological approach based on Compton-like Feynman
amplitudes, we study multi-pion production in antiproton nucleon collisions.
The main interest of this reaction is related to the possibility to study the
properties of the presumable $\bar N N$ atom and of its resonances. For the
case of formation of a scalar or pseudoscalar resonant state, with
$I^G(J^{P})=1^-(0^{\pm}),~0^+(0^-)$ numerical results are obtained. The
differential cross section in an experimental set-up where the pions invariant
mass is measured, is given with explicit dependence on the lepton pair and
pions invariant mass.
