Quasifission and fusion-fission lifetime studies for the superheavy element Z=120

We study the quasifission and fusion-fission lifetimes for a number of fusion reactions used to synthesize the superheavy element Z = 120 using a statistical method within the framework of the dinuclear system model. In particular, influence of the target orientation and angular momentum on such lifetimes have been investigated. The quasifission and fusion-fission lifetimes have been compared very well with that of available experiments on successful superheavy element synthesis. We notice further the predicted quasifission and fusion-fission lifetimes of the projectile-target combinations used for the synthesis of the superheavy element Z = 120 also show the similar trend. Furthermore, the fusion-fission lifetime is seen to somewhat decrease with the increase of the angular momentum as well as beam energy. Little effect is seen on fusion barrier of the reaction and fission barrier of superheavy compound nucleus. Variation of quasifission lifetime is also not much with orientation angle, beam energy and fission barrier of the superheavy compound nuclei. Hence, this lifetime study does not provide any good reason why the attempted reactions have failed to synthesize the superheavy nuclei Z = 120. Furthermore, consideration of the fusion barrier, fissility, mass asymmetry, deformation parameter, fission barrier, etc., leads us to reveal that optimal colliding energy is important to have the largest evaporation residue cross section for any chosen reaction so that it is well within the measurable limit for a specific experimental set up.

Automated summary

This study examines the quasifission and fusion-fission lifetimes of fusion reactions used to synthesize the superheavy element Z = 120 using a statistical method within the dinuclear system model framework. The results show good agreement with experimental data, but indicate a slight decrease in fusion-fission lifetime with increasing angular momentum and beam energy.