Study of resonant processes for multi-pion production in $\bar{p}+p\to {\ell }^{+}+{\ell }^{-}+n_{\ddot{I}}€\ddot{I}€$ annihilation

Abstract

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.

9 pages, 4 figures