True absorption and scattering of 50 MeV pions

The inclusive pion inelastic scattering and true absorption cross sections at 50 MeV were measured for π⁺ on natural Li, C, Fe, Nb, and Bi and for π^- on C, Fe, and Bi. The results show that π^- cross sections are much larger than π⁺, the difference being significantly larger than expected from a simple Coulomb calculation. In particular, in ¹²C the absorption of negative pions is about twice that of positive pions.NUCLEAR REACTIONS Li, C, Fe, Nb, Bi (π⁺, π⁺^') and C, Fe, Bi (π^-, π^-^'), E_π=50 MeV; measured σ(θ_π^'), transmission; deduced σabsorption.