Systematical calculations of the 136Xe(136Xe,xn)272-xHs reaction: Effects of quasifission in the early stage of the fusion process

We have reevaluated the Xe-136(Xe-136,xn)(272-x)Hs reaction with a modified fusion-by-diffusion model. In this model, the early dynamics of neck growth is taken into account in terms of the two-dimensional Langevin equation. By numerically solving the dynamic equations, the probability distribution of the separation between the surfaces of two approaching nuclei at the injection point in an asymmetric fission valley is obtained. Before reaching the asymmetric fission valley, the strong electrostatic repulsion may force the system to redisintegrate in a quasifissionlike process. We find that more than 80% of quasifission events occur during the transition from dinuclear to mononuclear regimes for the Xe-136 + Xe-136 reaction. This observation gives credence to the conjecture that the quasifission reaction channel most likely occurs in an early stage of collective motion. By incorporating this essential physical ingredient into the calculations, the modified fusion-by-diffusion model nicely accounts for the experiment of the Xe-136 + Xe-136 reaction performed in Dubna.