Study of the threshold anomaly in the elastic scattering of d+$^{197}$Au

TL;DR

This study investigates the elastic scattering of deuterons on gold nuclei near the Coulomb barrier, revealing a breakup threshold anomaly indicative of weakly bound nuclear behavior through experimental measurements and optical model analysis.

Contribution

It provides the first detailed analysis of the threshold anomaly in d+^{197}Au scattering using two optical potential models across a range of energies.

Findings

Identification of a critical interaction distance of 2.49 fm.

Observation of the breakup threshold anomaly near the Coulomb barrier.

Consistent results from two different optical potential models.

Abstract

Measurements of the elastic scattering angular distribution for the d+$^{197}$Au system were carried out covering deuteron incident energies in the range from 5 to 16 MeV, i.e. approximately 50% below and above the Coulomb barrier. A critical interaction distance of $d_I$= 2.49 fm was determined from these distributions, which is comparable to that of the radioactive halo nucleus $^{6}$He. The experimental angular distributions were systematically analyzed using two alternative models: the semi-microscopic Sao Paulo and the effective Woods-Saxon optical potentials, for which the best-fitting parameters were determined. These potentials, integrated in the vicinity of the sensitivity radius, were calculated for each energy. For both models, the energy dependence of these integrals presented the breakup threshold anomaly around the coulomb barrier, a typical signature of weakly bound nuclei.