Coincidence measurements of pion single charge exchange in the Δ‐resonance region

We discuss the first coincidence measurements of the reaction (π+,π0p). The were performed primarily on 16O at Tπ+=165 and 245 MeV. The reaction is shown to have a clear quasi‐free signature. The π0 energy spectra for events corresponding to removal of a p‐shell nucleon are compared to predictions of Δ‐hole model calculations; the calculation generally underestimate the (π+, π0p) cross sections. At forward pion angles experimental ratios between the (π+, π+p) and (π+, π0p) reactions are found to differ significantly from estimates using free π‐N cross sections. A study of the A‐dependence of the (π+, π0p) process indicate that the cross section is roughly constant over the examined range of nuclear masses.