Role of neutron transfer in sub-barrier fusion

Abstract

The fusion excitation function of $^{35}\mathrm{Cl}+^{130}\mathrm{Te}$ system has been measured in a wide energy range, i.e., ${E}_{\mathrm{c}.\mathrm{m}.}=94--121.6$ MeV, from sub-barrier to above-barrier energies and compared with the $^{37}\mathrm{Cl}+^{130}\mathrm{Te}$ system to investigate the role of neutron transfer channels in sub-barrier fusion cross-section enhancement. In comparison, the reduced fusion excitation function of $^{35}\mathrm{Cl}+^{130}\mathrm{Te}$ system shows a significant enhancement over the $^{37}\mathrm{Cl}+^{130}\mathrm{Te}$ system at sub-barrier energies. This enhancement is correlated with the presence of six positive $Q$-value neutron transfer channels in the $^{35}\mathrm{Cl}+^{130}\mathrm{Te}$ system compared to none in the $^{37}\mathrm{Cl}+^{130}\mathrm{Te}$ system. Aiming to probe how fusion at sub-barrier energies responds to different coupling schemes, the excitation functions of both the systems have been analyzed in the framework of the coupled-channels approach on the same footing. The results and coupled-channels analysis presented in this work hints towards the importance of neutron transfer channels in sub-barrier fusion in addition to the inclusion of inelastic excitations of interacting partners. The findings of this work are discussed in light of the conclusions presented by Kohley et al. [Phys. Rev. Lett. 107, 202701 (2011)], in which the role of positive $Q$-value neutron transfer channels in sub-barrier fusion was studied.