Study of resonant processes for multi-pion production in p¯+p→ℓ++ℓ−+nππ annihilation

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 N¯N atom and of its resonances. For the case of formation of a scalar or pseudoscalar resonant state, with IG(JP)=1−(0±),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.