Hindrance in the fusion of $^{48}$Ca+$^{48}$Ca

TL;DR

This paper investigates the fusion hindrance in $^{48}$Ca+$^{48}$Ca using coupled-channels calculations with different ion-ion potentials, highlighting the importance of the M3Y+repulsion potential in reproducing experimental data.

Contribution

The study demonstrates that the M3Y+repulsion potential with an adjusted radius effectively models fusion hindrance phenomena in calcium-48 fusion reactions.

Findings

Standard Woods-Saxon potential fails to reproduce low-energy fusion data.

M3Y+repulsion potential accurately fits the experimental fusion hindrance.

High-lying state polarization affects the inferred nuclear radius.

Abstract

The coupled-channels technique is applied to analyze recent fusion data for $^{48}$Ca+$^{48}$Ca. The calculations include the excitations of the low-lying $2^+$, $3^-$ and $5^-$ states in projectile and target, and the influence of mutual excitations as well as the two-phonon quadrupole excitations is also investigated. The ion-ion potential is obtained by double-folding the nuclear densities of the reacting nuclei with the M3Y+repulsion effective interaction but a standard Woods-Saxon potential is also applied. The data exhibit a strong hindrance at low energy compared to calculations that are based on a standard Woods-Saxon potential but they can be reproduced quite well by applying the M3Y+repulsion potential with an adjusted radius of the nuclear density. The influence of the polarization of high-lying states on the extracted radius is discussed.