The inclusive pion inelastic scattering and true absorption cross sections at 50 MeV were measured for ${\pi }^{+}$ on natural Li, C, Fe, Nb, and Bi and for ${\pi }^{-}$ on C, Fe, and Bi. The results show that ${\pi }^{-}$ cross sections are much larger than ${\pi }^{+}$, the difference being significantly larger than expected from a simple Coulomb calculation. In particular, in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ the absorption of negative pions is about twice that of positive pions.

NUCLEAR REACTIONS Li, C, Fe, Nb, Bi (${\pi }^{+}, {{\pi }^{+}}^{\prime }$) and C, Fe, Bi (${\pi }^{-}, {{\pi }^{-}}^{\prime }$), $E_{\pi }=50\mathrm{}$ MeV; measured $\sigma \left({\theta }_{{\pi }^{\prime }}\right)$, transmission; deduced ${\sigma }_{\mathrm{absorption}}$.

• Received 15 March 1983

DOI:https://doi.org/10.1103/PhysRevC.28.2548