Competition between fusion-fission and quasifission processes in the ${}^{32}$S+${}^{182,184}$W reactions

Abstract

The angular distributions of fission fragments for the ${}^{32}$S+${}^{184}$W reaction at center-of-mass energies of 118.8, 123.1, 127.3, 131.5, 135.8, 141.1 and 144.4 MeV were measured. The experimental fission excitation function is obtained. The fragment angular anisotropy (${\mathcal{A}}_{\exp }$) is found by extrapolating the each fission angular distributions. The measured fission cross sections of the ${}^{32}$S+${}^{182,184}$W reaction are decomposed into fusion-fission, quasifission and fast fission contributions by the dinuclear system model. The total evaporation residue excitation function for the ${}^{32}$S+${}^{184}$W reaction calculated in the framework of the advanced statistical model is in good agreement with the available experimental data up to about $E_{c.m.}\approx 160$ MeV. The theoretical descriptions of the experimental capture excitation functions for both reactions and quantities $K_0^2$, $<{\ell }^2>$ and ${\mathcal{A}}_{\exp }$ which characterize angular distributions of the fission products were performed by the same partial capture cross sections at the considered range of beam energy.

Comments: 28 pages, 13 figures, submitted to Phys. Rev. C