Breakup threshold anomaly in the elastic scattering of the 9Be + 80Se system

Elastic scattering angular distributions for the 9Be + 80Se system were measured at eleven energies from below to above the Coulomb barrier. The experimental elastic scattering cross sections were analyzed within the framework of the optical model to study the energy dependence of the potential. Two different potentials were used: an energy-dependent phenomenological Woods-Saxon potential and a double folding São Paulo potential. For these two potentials, the energy dependence of the real and imaginary strengths shows consistent with the presence of the breakup threshold anomaly. An alternative method is proposed for calculating the dispersion relation between the real and imaginary parts of the optical potential based on bivariate random sampling obtained from the covariance matrix of the adjusted experimental angular distributions.