Why does neutron transfer play different roles in sub-barrier fusion reactions $^{32}$S+$^{94,96}$Zr and $^{40}$Ca+$^{94,96}$Zr?

TL;DR

This paper investigates how neutron transfer influences sub-barrier fusion reactions involving zirconium isotopes and calcium, revealing different roles of neutron transfer based on reaction specifics using quantum diffusion analysis.

Contribution

It introduces a quantum diffusion approach to analyze the impact of neutron transfer with positive and negative Q-values on sub-barrier fusion enhancement.

Findings

Neutron transfer effects vary significantly between different reaction systems.

Positive Q-value neutron transfer enhances fusion in some systems.

The study provides a unified analysis of multiple fusion reactions.

Abstract

The sub-barrier capture (fusion) reactions $^{32}$S+$^{90,94,96}$Zr, $^{36}$S+$^{90,96}$Zr, $^{40}$Ca+$^{90,94,96}$Zr, and $^{48}$Ca+$^{90,96}$Zr with positive and negative $Q$-values for neutron transfer are studied within the quantum diffusion approach and the universal fusion function representation. For these systems, the s-wave capture probabilities are extracted from the experimental excitation functions and are also analyzed. Different effects of the positive $Q_{xn}$-value neutron transfer in the fusion enhancement are revealed in the relatively close reactions $^{32}$S+$^{94,96}$Zr and $^{40}$Ca+$^{94,96}$Zr.