Formulation of the Coulomb effects of spectator fragments on pions from heavy ion collisions

Coulomb effects on heavy-ion pion production cross sections are formulated in terms of weighted averaging over various projectile fragments. Satisfactory fits to zero-degree pion data are found for Ar + C and Ne + C systems. The fragment distributions of excited compound nuclei before nucleon evaporation must be used. Average charge $Z_{\mathrm{eff}}$ values are determined and compared with those from an experimental paper. In the heavy-ion energy range of the 0° pion studies ($300 \mathrm{MeV} \lesssim \frac{E}{A}\lesssim 600 \mathrm{MeV}$) it is clear that target-projectile factorization for fragmentation cross sections does not hold; that is, the relative yields of projectile fragments are not target independent.