Comparison of pion- and photon-induced reactions on 12C

The proton spectra from pion- and photon-induced reactions on 12C at the Δ(3/2,3/2) resonance are found to be very similar in shape, and in their variation with angle. It seems reasonable to assume that these protons arise from a common reaction mechanism (Δ production) for the two projectiles. The absolute cross sections for producing protons with pions and with photons are in roughly the same ratio as the total inelastic pion yield to the total photopion yield.