Meson retardation in deuteron electrodisintegration

The effect of meson retardation in $NN$-interaction and exchange currents on deuteron electrodisintegration is studied in a coupled channel approach including $NN$-, $N \Delta$- and $\pi d$-channels. It is shown that the influence of retardation depends on the energy regime: Whereas below $\pi$-threshold calculations with static and retarded operators yield almost identical results, they differ significantly in the $\Delta$-region. Especially, the longitudinal and the longitudinal-transverse interference structure functions are strongly affected.