Deciphering the influence of neutron transfer in Si-based fusion reactions around the Coulomb barrier

TL;DR

This study investigates how neutron transfer channels influence fusion reactions near the Coulomb barrier in Si-based systems, highlighting the significant role of up to 2-neutron transfer with positive Q-values in sub-barrier fusion enhancement.

Contribution

It provides a detailed analysis of neutron transfer effects on fusion dynamics using coupled channel models and compares different potential parametrizations, offering new insights into transfer channel impacts.

Findings

Up to 2n transfer with positive Q-values significantly enhances sub-barrier fusion.

More than 2n transfer channels show negligible impact despite positive Q-values.

GRAZING calculations align with coupled channel results for 2n transfer cross-sections.

Abstract

Purpose: We aim to investigate the role of a few neutron transfer channels on the dynamics of fusion reactions around the Coulomb barrier by judicially selecting 11 different $^{28,30}$Si-induced systems. These reactions are chosen in such a way that they possess positive and negative Q-values for neutron transfer channels to make the comparison more apparent. Furthermore, a comparative study on fusion barrier parameters using different proximity potentials and parametrizations is also a prime goal. Method: A channel coupling approach within the framework of a semiclassical model is being used to investigate the role of multi-neutron transfer with positive Q-values on fusion phenomena near and below the Coulomb barrier. The fusion barrier parameters have been extracted and analyzed within the framework of seven different potential models. Results: The sub-barrier fusion enhancement compared to the one-dimensional barrier penetration model (uncoupled) is investigated by considering collective excitations in colliding nuclei and multi-neutron transfer channels with Q $>$ 0 within the channel coupling model. Furthermore, GRAZING calculations are performed to predict the cross-section of target-like fragments after 2n pickup transfer. Conclusion: All the fusion excitation functions (EFs) have been successfully explained by the coupled channel calculations using the channel coupling model. Only the significant effect of up to 2n pickup transfer with Q $>$ 0 was found on sub-barrier fusion. Despite having positive Q values for transfer channels, no noticeable impact of more than 2n transfer was observed. GRAZING predictions are grossly in the same order as the quantitative contribution of 2n transfer channels observed by channel coupling model calculations.