Pion charge exchange to the isovector giant dipole state at energies above the 3-3 resonance

Small-angle differential cross sections for the (${\ensuremath{\pi}}^{+}$,${\ensuremath{\pi}}^{0}$) reaction have been measured at energies of 300, 425, and 500 MeV for the isovector giant dipole resonance in a range of targets. Peak differential cross sections are inferred by extrapolation in angle. The target-mass dependence of these cross sections, normalized to the expected sum rule, shows the same mass dependence at 425 MeV that is observed for isobaric analog state transitions.