Diffraction theory and the double-charge-exchange reactionO18(π+, π−)Ne18

The angular distribution and the excitation function of the reaction ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}({\pi }^{+}, {\pi }^{-}){}_{}{}^{18}{}_{}{}^{}\mathrm{Ne}$ (double isobaric analog state) can be well understood in the framework of a coupled-channel diffractive scattering theory provided we include higher-order processes. Use of a scaling theory allows an essentially parameter-free calculation of these processes and makes possible the study of effects arising from finer aspects of nuclear structure such as the core excitation of ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$.