Influence of Entrance Channel Parameters on FICF in Near-Barrier Fusion with Radioactive Targets

The study of fraction of the incomplete fusion i.e FICF(%) is crucial for understanding heavy-ion reaction mechanisms, superheavy element synthesis, and astrophysical nucleosynthesis. Hence, in this study, we analyzed 16 experimentally available heavy-ion fusion reactions. Theoretical fusion cross-sections were calculated using Wong's formula and compared with experimental data from the literature. Additionally, we examined the effect of entrance channel parameters on the percentage of fraction of incomplete fusion i.e FICF(%). Specifically, we investigated the influence of charge asymmetry (αz) and mass asymmetry (ηA) on FICF(%) across different energy regimes. At sub-barrier energies (Ecm/Vb=0.9-1) FICF(%) increases with asymmetry for reactions such as 238U+32S, 238U+35Cl, 238U+40Ca, 26Mg+248Cm, 32S+238U, and 208Pb+27Al. However, for Ecm/Vb >1, FICF(%) generally decreases. Furthermore, we explored the impact of key entrance channel parameters, including the Coulomb interaction, charge product, fissility, zeta parameter, and alpha decay energy. Across three energy regimes (Ecm/Vb=0.9-1, 1-1.1, and 1.1-1.2), no systematic FICF(%) variation was observed below the barrier due to Coulomb repulsion. However, near and above the barrier, FICF(%) increased systematically with all parameters, as higher interaction energy enhances nuclear breakup and transfer processes. These findings highlight the crucial role of the entrance channel parameters in governing the fusion and incomplete fusion probabilities in heavy-ion collisions.