Long range effects on the optical model of 6He around the Coulomb barrier

TL;DR

This paper analyzes elastic scattering of 6He on aluminum and lead near the Coulomb barrier, revealing long-range effects and the importance of Coulomb dipole polarization using microscopic and phenomenological models.

Contribution

It introduces a comprehensive optical model including a microscopic double folding potential and Coulomb dipole polarization, validated by four-body calculations for weakly bound 6He.

Findings

Confirmation of long-range components in 6He+208Pb scattering

Validation of Coulomb dipole polarization effects

Insights into the optical potential of weakly bound nuclei

Abstract

We present an optical model (OM) analysis of the elastic scattering data of the reactions 6He+27Al and 6He+208Pb at incident energies around the Coulomb barrier. The bare part of the optical potential is constructed microscopically by means of a double folding procedure, using the Sao Paulo prescription without any renormalization. This bare interaction is supplemented with a Coulomb dipole polarization (CDP) potential, which takes into account the effect of the dipole Coulomb interaction. For this CDP potential, we use an analytical formula derived from the semiclassical theory of Coulomb excitation. The rest of the optical potential is parametrized in terms of Woods-Saxon shapes. In the 6He+208Pb case, the analysis confirms the presence of long range components, in agreement with previous works. Four-body Continuum-Discretized Coupled-Channels calculations have been performed in order to better understand the features of the optical potentials found in the OM analysis. This study searches to elucidate some aspects of the optical potential of weakly bound systems, such as the dispersion relation and the long range (attractive and absorptive) mechanisms.