Pion Production Ratios. II

Abstract

The ratio of positive to negative pion production is considered for protons of ∼0.35-Bev energy incident on nuclei. The model of a single excited nucleon is used. It is argued that (i) at these energies the meson-producing nucleon state is about equally likely to be $T=\frac{1}{2}$ or $T=\frac{3}{2}$; (ii) structural effects in the final nucleus inhibit ${\pi }^{-}$ production in light nuclei, where isotopic spin is conserved. Effect (ii) may be partly responsible for the observed difference in shape of ${\pi }^{+}$ and ${\pi }^{-}$ production curves as a function of $A$.