Role of neutron transfer in sub-barrier fusion

The fusion excitation function of Cl-35 + Te-130 system has been measured in a wide energy range, i.e., E-c.m. = 94-121.6 MeV, from sub-barrier to above-barrier energies and compared with the Cl-37 + Te-130 system to investigate the role of neutron transfer channels in sub-barrier fusion cross-section enhancement. In comparison, the reduced fusion excitation function of Cl-35 + Te-130 system shows a significant enhancement over the Cl-37 + Te-130 system at sub-barrier energies. This enhancement is correlated with the presence of six positive Q-value neutron transfer channels in the Cl-35 + Te-130 system compared to none in the Cl-37 + Te-130 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.