Present status of electromagnetic reactions on the deuteron above pion threshold

Abstract

The present status of the theoretical description of electromagnetic reactions on the deuteron above pion threshold is reviewed. Three major topics are considered: (i) retardation effects in $π$-meson exchange contributions to $NN$-interaction and meson exchange currents in deuteron photodisintegration above $π$-threshold in the $Δ$-resonance region, (ii) off-shell effects in the one-body current treated in a simple pion cloud model in deuteron photodisintegration in and above the $Δ$-resonance region, and (iii) final state interaction effects in photoproduction of $π$ and $η$ mesons on the deuteron.