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

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 $Z_{\mathrm{T}}\approx 80$.

Comments: 10 pages with 3 figures