Importance of neutron transfer channels in sub-barrier fusion reaction mechanism

Heavy ion fusion reaction has been extensively studied for the last two decades. Fusion cross-sections show large enhancement with respect to theoretical prediction in sub-barrier energy region. It is well known that the enhancement occurs due to nuclear vibration, deformation and nucleon transfer. The influence of nuclear vibration and deformation is well described within the framework of coupled channel (CC) calculations. However, the role of neutron transfer is not yet explained. Experimental investigations have shown that large enhancement in fusion cross-sections is due to neutron transfer channels with positive Q value. But, few systems did not show any enhancement in spite of having positive Q value neutron transfer channels. Hence, Q value is not the only criteria to infer the importance of neutron transfer on fusion. In a recent article, it was stated that enhancement is related to the increase in deformation of interacting nuclei after neutron transfer. In other words, fusion will be weakly influenced by positive Q value neutron transfer channel if deformation of nuclei do not change or decrease after transfer. Moreover, it was recently reported that only valence neutrons i.e. 1n and 2n transfer channel with positive Q value has significant impact on sub-barrier fusion