Study of the threshold anomaly in the elastic scattering of d + 197Au

Measurements of the elastic scattering angular distribution for the d + 197Au 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 dI = 2.49 fm was determined from these distributions, which is comparable to that of the radioactive halo nucleus 6He. The experimental angular distributions were systematically analyzed using two alternative models: the semimicroscopic São 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.