Helicity dependence of the [FORMULA]d [FORMULA][FORMULA]NN reactions in the [FORMULA] -resonance region

The helicity dependence of the differential cross-section for the [FORMULA]d[FORMULA][FORMULA]NN reactions has been measured for the first time in the [FORMULA] -resonance region. The measurement was performed with the large-acceptance detector DAPHNE at the tagged photon beam facility of the MAMI accelerator in Mainz. The data show that the main reaction mechanisms for the [FORMULA]NN channels are the quasi-free N[FORMULA] processes on one bound nucleon with nuclear dynamics playing a minor role. On the contrary, for the [FORMULA]np channel nuclear mechanisms involving the reabsorption of the photoproduced [FORMULA] by the np pair have to be taken into account to reproduce the experimental data.