Dynamics of fusion-fission process in superheavy mass region

The fusion‐fission process for the synthesis of superheavy elements is discussed on the basis of the fluctuation‐dissipation model. Recently the experiments at Dubna on fission of superheavy nuclei were carried out, and the mass and total kinetic energy distributions of fission fragments were measured. By analyzing the mass distribution of fission fragments, we can distinguish between fusion‐fission process and quasi‐fission process. We employ three‐dimensional Langevin equation. We find almost all of the mass symmetric fission events come from the quasi‐fission process in the superheavy mass region. In order to classify the fusion‐fission paths and compare with the experimental data directly, we analyze the pre‐scission neutron emission in the correlation with fission fragments. The neutron multiplicity depends on the travelling time of the trajectory. It is useful to investigate the fusion‐fission process.