Pion double charge exchange above the Δ(1232) resonance

Abstract First measurements of exclusive cross sections for the ( π + , π − ) reaction at incident energies of 300–500 MeV are reported. For the analog-state transitions in 14 C and 18 O the 5° cross sections are found to remain nearly constant in this energy interval. This behavior is in disagreement both with predictions based on six-quark cluster models and with simple expectations based on recent single-charge-exchange measurements.