Angular momentum and cross sections for fusion with weakly bound nuclei: breakup, a coherent effect

Abstract

Results for the cross section and average angular momentum for complete fusion at energies around the Coulomb barrier are presented for ⁷Li with ¹⁶⁵Ho. Comparison of the cross sections with a one-dimensional barrier penetration model, using a potential consistent with the measured elastic scattering, showed a reduction above the barrier and an enhancement below it. An increase in the measured average angular momentum, <l>, above the barrier and its consistency with that obtained from the fusion excitation function for weakly bound nuclei, is reported. These results together with a reanalysis of existing data conclusively demonstrate that the effect of breakup on fusion is coherent, like coupling to any nonelastic channel.