Model for Production ofπ+andπ−by Protons from Nuclei

We have modified the conventional semiclassical model for pion production from nuclei by including charge exchange of the outgoing pions and by dropping the forward-production approximation. We find good agreement with the general features of the ${\pi }^{+}$ and ${\pi }^{-}$ production by 740-MeV protons from various nuclei, as measured recently by Cochran et al.