The Onset of Nuclear Structure Effects in Near-Barrier Elastic Scattering of Weakly-Bound Nuclei: $^6$He and $^6$Li Compared

TL;DR

This study investigates how nuclear structure effects influence near-barrier elastic scattering of weakly-bound nuclei, specifically $^6$He and $^6$Li, revealing that Coulomb dipole breakup effects are prominent only with heavy targets of around $Z_T \,=\ 80$.

Contribution

The paper provides a systematic analysis of Coulomb dipole breakup effects in elastic scattering of weakly-bound nuclei using CDCC calculations across various target charges.

Findings

Coulomb dipole breakup effects are significant for targets with $Z_T \approx 80$.

Deviations from Fresnel diffraction are linked to nuclear structure and Coulomb coupling.

The effect's visibility depends on the target's atomic number.

Abstract

The elastic scattering of the halo nucleus $^6$He from heavy targets at incident energies near the Coulomb barrier displays a marked deviation from the standard Fresnel-type diffraction behavior. This deviation is due to the strong Coulomb dipole breakup coupling produced by the Coulomb field of the heavy target, a specific feature of the nuclear structure of $^6$He. We have performed Continuum Discretized Coupled Channels calculations for the elastic scattering of $^{6}$He and $^6$Li from $^{58}$Ni, $^{120}$Sn, $^{144}$Sm, $^{181}$Ta and $^{208}$Pb targets in order to determine the range of $Z_{\mathrm T}$ where this nuclear-structure specific coupling effect becomes manifest. We find that the strong Coulomb dipole breakup coupling effect is only clearly experimentally distinguishable for targets of $Z_{\mathrm T} \approx 80$.