The pion-nucleus single charge exchange scattering matrix is described by the nonstatic theory based on the delta-hole formalism which is quite successful for the pion-nucleus elastic scattering in the (3,3) resonance energy region. The calculated excitation function of the ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$(${\pi }^{+}$, ${\pi }^0$)${}_{}{}^{13}{}_{}{}^{}\mathrm{N}_{\mathrm{q}.\mathrm{s}.\mathrm{}}^{}{}_{}{}^{}$ charge exchange scattering cross section becomes flat between the pion kinetic energies 70 and 230 MeV, but the theoretical integrated cross sections are roughly a factor of 3 less than the observed ones. The observed shape of angular distribution at 150 MeV is well reproduced by our theory, although the absolute values of the calculated angular distribution are slightly smaller than the measurements.

NUCLEAR REACTIONS Pion-nucleus single charge exchange scattering. Delta-hole formalism, pion energy 70-230 MeV.

• Received 2 December 1980

DOI:https://doi.org/10.1103/PhysRevC.24.1604