Role of non-collective excitations in low-energy heavy-ion reactions

TL;DR

This paper explores how non-collective single-particle excitations influence low-energy heavy-ion reactions, revealing their role in modifying barrier penetrability and distribution near the Coulomb barrier.

Contribution

It introduces a novel approach using random matrix theory to model single-particle excitations and solves coupled-channels equations to analyze their effects.

Findings

Single-particle excitations hinder barrier penetrability above the Coulomb barrier.

These excitations lead to a smeared barrier distribution.

The model explains differences in quasi-elastic barrier distributions in specific nuclear systems.

Abstract

We investigate the effect of single-particle excitations on heavy-ion reactions at energies near the Coulomb barrier. To this end, we describe single-particle degrees of freedom with the random matrix theory and solve the coupled-channels equations for one-dimensional systems. We find that the single-particle excitations hinder the penetrability at energies above the barrier, leading to a smeared barrier distribution. This indicates that the single-particle excitations provide a promising way to explain the difference in a quasi-elastic barrier distribution recently observed in $^{20}$Ne + $^{90,92}$Zr systems.