Pions modes of excitation in nuclei

Pionic modes of excitation in nuclei in pion-nucleus reactions are discussed. The model based on the π-baryon effective lagrangians and the physical masses of nucleon, Δ and N* resonances is applied to pion-nucleus interactions. Using the effective lagrangians the OPE model as particle-hole interaction is described. A schematic picture of the spectrum of pionic excitations in nuclear matter is determined by the singularities of the pion-nuclear response function. The most interesting region is the range of the Δ(1232) propagation in nuclei. High momentum transfer properties of pion-like nuclear states are considered in connection with pion condensation in nuclear matter