Dynamical calculation for fusion–fission probability in superheavy mass region, where mass symmetric fission events originate

Abstract

We discuss dynamically the fusion–fission mechanism in the superheavy mass region. By analyzing the mass distribution of fission fragments, we distinguish between the fusion–fission process and the quasi-fission process. We investigate these two processes using the fluctuation–dissipation model. The three-dimensional Langevin equation is employed. We classify the dynamical process by analyzing the trajectory in the nuclear deformation space. In the superheavy mass region, we found that 90–99% of mass symmetric fission events come from the quasi-fission process, in which the system hardly reaches the spherical region. The fusion cross section is also estimated precisely.