On Importance of Inelastic Rescatterings in Pion Double Charge Exchange on Nuclei

Different aspects of the Gribov--Glauber approach for calculation of inclusive pion double charge exchange (DCX) on nuclei are investigated. Recently we have shown that inelastic rescatterings (IR) with two (and more) pions in the intermediate states give an important contribution to the process of DCX at energies above $\sim0.6 GeV$. In this paper we use the one pion exchange model to study in details amplitudes of two pion production. This allows us to verify theoretical assumptions made in the previous paper and to predict cross section for the forward inclusive pion DCX at energies $\ga1 GeV$, where IR dominate over the conventional DCX mechanism of two sequential single charge exchanges.