Background: The influence of inelastic excitations on sub-barrier fusion enhancement is well established; however, the transfer channel effect can be surprising. Recently, it has been shown that the $2n$ transfer channel is mainly responsible for sub-barrier fusion enhancement despite having a positive-$Q$ value for many-neutron transfer channels. Moreover, some systems do not show enhancement even if they possess positive-$Q$-value transfer channels. It has also been reported that enhancement can be found in those systems for which deformation of nuclei increases after neutron transfer.

Background: Heavy-ion fusion cross-sections at sub barrier energies are found to be enhanced by orders of magnitude as compared to the predictions of one-dimensional barrier penetration model (1-D BPM). The coupling of various internal degrees of freedom has been employed to decrypt the mechanism responsible for the observed sub-barrier fusion enhancement. However, the unambiguous role of multi-neutron transfer channels in the sub-barrier domain is still elusive.

The phenomenon of enhanced fusion cross-section as compared to the theoretical predictions of 1-D BPM has been extensively studied over the past few decades. However, the unambiguous role of neutron transfer channels on the sub-barrier fusion enhancement is still elusive in most cases. Fusion cross-section measurements ≈ 15% below and above the Coulomb barrier were performed to elucidate the mechanisms responsible for the experimentally observed sub-barrier fusion enhancement. Coupled-channels calculations using CCFULL were used to decipher the reaction dynamics. CC calculations explained the fusion excitation function for ²⁸Si + ^116,120Sn systems after the inclusion of inelastic excitations along with a pair transfer. However, the observed behavior for the ²⁸Si + ¹²⁴Sn system could not be explained. The fusion barrier distribution has been extracted from the experimental data to unveil the various channels coupled in the concerned rection. A single uncoupled barrier was transformed into a distribution of barriers depicting the presence of different channels coupled in the reaction. The results indicate a significant effect from multi-neutron transfer channels on the fusion dynamics.