Diffractive Dissociation of Negative Pions off Complex Nuclei at 156 Gev/c.

A pion-nucleus scattering experiment has been performed at Fermi National Accelerator Laboratory with a 156 GeV/c incident negative pion beam on various nuclear targets. The data are dominated by diffractive dissociation of the incident pion into three charged pions. The differential cross section was measured in the region -t < .5. These data are presented with a fit to an optical model. Some evidence is also found for A(,2) production.