A pion optical potential is constructed which incorporates the Δ dynamics found to be important in Δ-hole analyses of pion scattering from light nuclei. These dynamics include Δ propagation, binding and Pauli blocking, and a Δ spreading potential. We employ a local density approximation for the medium-modified Δ propagator, resulting in a computationally flexible tool for the analysis of pion-nucleus data. We reproduce the Δ-hole results for π${\mathrm{-}}^{16}$O scattering satisfactorily. Elastic ${\pi }^{\pm }$${\mathrm{-}}^{208}$Pb scattering is described very well with the same strongly damping spreading potential found for light nuclei. The pion wave functions in the medium are substantially modified by the Δ dynamics.

• Received 1 July 1985

DOI:https://doi.org/10.1103/PhysRevC.33.974