Uncertainties of optical-model parameters for the study of the threshold anomaly

D. ABRIOLA; A. ARAZI; J. E. TESTONI; F. GOLLAN; G. V. MARTÍ

Maresias

Workshop; XXXVII Reunião de Trabalho sobre Física Nuclear no Brasil,; 2014

Sociedade Brasileira de Fisica

In the analysis of elastic-scattering experimental data, optical-model parameters(usually, depths of real and imaginary potentials) are fitted and conclusions are drawn analyzingtheir variations at bombardment energies close to the Coulomb barrier (threshold anomaly).The judgement about the shape of this variation (related to the physical processes producingthis anomaly) depends on these fitted values but the robustness of the conclusions stronglydepends on the uncertainties with which these parameters are derived. We will show thatprevious published studies have not used a common criterium for the evaluation of the parameteruncertainties. In this work, a study of these uncertainties is presented, using conventionalstatistic tools as well as bootstrapping techniques. As case studies, these procedures are appliedto re-analyze detailed elastic-scattering data for the 12C + 208Pb and the 6Li + 80Se systems