Compound-Nucleus Decay along the Mass-Asymmetry Coordinate and the Role of the Businaro-Gallone Point

Abstract

Fragments with atomic numbers covering the entire range of the mass-asymmetry coordinate ($Z=1$ to $Z=\frac{{Z}_{\mathrm{CN}}}{2}$) were observed from the decay of compound nuclei (CN) produced in reactions of 7.4- and 8.4-MeV/nucleon $^{74}\mathrm{Ge}$, $^{93}\mathrm{Nb}$, and $^{139}\mathrm{La}$ with $^{9}\mathrm{Be}$ and $^{12}\mathrm{C}$. The evolution of the charge distribution with increasing mass of the compound nucleus ($A=83 \mathrm{to} 151$) reflects the topological change in the potential-energy surface associated with crossing the Businaro-Gallone point.