Measurement of the differential cross sections for π−p charge-exchange scattering in the region of the low-lying P11, S11, and D13 resonances

The differential cross sections for the reaction π−p → π0n were measured for scattering angles in the backward hemisphere. The experiment was performed by using the pion channel of the synchrocyclotron installed at the Petersburg Nuclear Physics Institute (PNPI, Gatchina), the momenta of incident pions being varied in the range between 456 and 710 MeV/c. The measurements were performed by recording the recoil neutron in coincidence with one of the photons from the decay process π0 → 2γ. The experimental facility used is described, and the results of the measurements are presented. These new results are characterized by a statistical accuracy higher than that of all results published previously and are in better agreement with the predictions of the partial-wave analysis (SM-95 version) performed by a group from Virginia Polytechnic Institute.