Impact of nucleon transfer channels on complete fusion in the Li6,7+Ni58 reactions near the Coulomb barrier

Abstract

Reactions involving weakly bound nuclei, both stable and radioactive, especially at energies near the Coulomb barrier remain at the forefront as topics to be understood, both experimentally and theoretically. Of special interest is the interplay between complete fusion, breakup, and direct reactions for these cases and the complete understanding of their influence on fusion, which arises because of the bottleneck in experimentally identifying complete fusion events. In this work we address this issue by measuring individual residue cross sections in the interaction of $^{6,7}\mathrm{Li}$ on a thin $^{58}\mathrm{Ni}$ target at energies around the barrier. Comparison with statistical model calculations and coupled reaction calculations allowed us to delineate the reaction products into those arising from complete fusion and those from direct transfer. At energies below the barrier where cross section enhancement is found to occur, the contribution of transfer channels to the total cross section is found to be large and had to be accounted for before assessing the enhancement above the one-dimensional barrier penetration predictions.