Pion-induced transport of pi mesons in nuclei - art. no. 034601

A large body of data for pion-induced neutral pion continuum spectra spanni ng outgoing energies near 180 MeV shows no dip there that might be ascribed to internal strong absorption processes involving the formation of Delta's . This is the same observation previously made for the charged pion continu um spectra. Calculations in an intranuclear cascade model or a cascade exci ton model with free-space parameters predict such a dip for both neutral an d charged pions. We explore several medium modifications to the interaction s of pions with internal nucleons that are able to reproduce the data for n uclei from Li-7 through Bi.