Ja n 20 00 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 ∼ 0.6 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 > ∼ 1 GeV , where IR dominate over the conventional DCX mechanism of two sequential single charge exchanges. The inclusive pion double charge exchange (DCX) reaction on nuclei, e.g. π − + A(Z, N) → π + + X (1) as a two-step transition on two like nucleons (protons) is described by the diagrams of three types (Fig.1(a), (b), (c)) which correspond to the Glauber picture of elastic (a), quasielastic (b) and inelastic (c) rescatterings. The conventional DCX mechanism of two sequential single charge exchanges (SSCX), i.e. the elastic rescattering, is found to describe [1], in general , experimental data on pion DCX at energies of the meson factories up 1