The differential cross section for the 12C(γ,π+ p) reaction has been measured in the Δ(1232) resonance region at high recoil momenta of the residual nuclear system. The data are analyzed under the assumption that the formation of the π+ p pairs may be interpreted as a γΔ++ → π+ p process which takes place on a Δ++ preexisting in the target nucleus. Estimates of the Δ++ momentum distribution ρΔ ++ (p̄) = 0.17 fm3 for a mean momentum p̄ = 300 ± 49 MeV/c as well as the number of Δ isobars per nucleon NΔ = 0.017 were obtained for 12C.
ASJC Scopus subject areas
- Nuclear and High Energy Physics