(γ, Δπ) on nuclei

It is shown that (γ, Δπ) on the nucleon is essentially determined by the seagull γN, Δπ term only. The corresponding total nuclear cross-section is cooperatively affected by the Δ and π self-energies which cause its spreading, but not by Fermi motion. It is argued that the total photoabsorption cross-section in the uncorrelated ππ region be hence decreased with respect to the nucleonic one, but not shadowed