Sub- and above barrier fusion of loosely bound $^6$Li with $^{28}$Si

TL;DR

This study measures fusion excitation functions of $^6$Li+$^{28}$Si across sub- and above-barrier energies, revealing enhanced sub-barrier fusion for $^6$Li compared to $^7$Li, with suppression at higher energies.

Contribution

First detailed comparison of sub- and above-barrier fusion for $^6$Li and $^7$Li with $^{28}$Si using gamma-ray detection methods.

Findings

Enhanced sub-barrier fusion for $^6$Li compared to $^7$Li.

Similar suppression of fusion cross sections at above-barrier energies for both isotopes.

Fusion cross sections increase at sub-barrier energies and decrease at above-barrier energies.

Abstract

Fusion excitation functions are measured for the system $^6$Li+$^{28}$Si using the characteristic $\gamma$-ray method, encompassing both the sub-barrier and above barrier regions, viz., $E_{lab}$= 7-24 MeV. Two separate experiments were performed, one for the above barrier region ($E_{lab}$= 11-24 MeV) and another for the below barrier region ($E_{lab}$= 7-10 MeV). The results were compared with our previously measured fusion cross section for the $^7$Li+$^{28}$Si system. We observed enhancement of fusion cross section at sub-barrier regions for both $^6$Li and $^7$Li, but yield was substantially larger for $^6$Li. However, for well above barrier regions, similar type of suppression was identified for both the systems.