Importance of entrance channel dynamics on heavy element formation Original Research Article

Fusion of two heavy nuclei leads to superheavy element formation only when the combined di-nucleus survives quasifission and leads to a compact compound nucleus, which in turn has to survive fission competition. Thus the formation of heavy elements is expected to be sensitive to the reaction conditions. Due to the small cross-sections of formation of superheavy nuclei, it is difficult to make detailed experimental studies of the conditions which influence their formation, however, investigations of reactions forming lighter compound nuclei can be of help. Measurements showing the importance of entrance channel properties on the subsequent reaction dynamics are presented. The data suggest that the suppression of complete fusion sets in for compound nuclei with Z between 80 and 90, even for mass-asymmetric fusion reactions. It is shown that the probability of survival of the evaporation residues increases dramatically with increasing neutron-richness of the combined system.