Signature of non-compound-nucleus fission at sub-barrier energies

We have extracted the experimental ${\mathit{J}}_{\mathrm{eff}}$ values from fission fragment angular distributions for the systems of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ${+}^{232}$Th, ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ ${+}^{232}$Th, and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ${+}^{238}$U at near- and sub-barrier energies. The ${\mathit{J}}_0$/${\mathit{J}}_{\mathrm{eff}}$ values for the cases of the above reactions and the heavy-ion reactions with projectiles heavier than A=24 show same systematic trend when plotted as a function of mean-square angular momentum of the fissioning nucleus. This observation leads us to the conjecture that the systematic trend of ${\mathit{J}}_0$/${\mathit{J}}_{\mathrm{eff}}$ bears the signature of non-compound-nucleus fission for the heavy-ion reactions with lighter projectiles at near- and sub-barrier energies.