On extraction of ground state deformation parameters from quasielastic and fusion excitation functions

Abstract

Measurement of back-angle quasielastic scattering around the barrier, in conjunction with coupled-channels calculation, has been reported in recent years to be an effective and sensitive method to determine ground state deformation parameters of nuclei in the sd-shell as well as rare earth regions. Consequently, quasielastic scattering has been proposed to be a promising probe for extraction of ground state deformation parameters of short-lived radioactive nuclei. Theoretical investigations of quasielastic scattering and fusion for the system ²⁸Si+¹⁴⁴Sm, within the coupled-channels framework, are reported here. Fusion barrier height distribution is derived from measured fusion excitation function by an analytic method assuming the former to be a multi-Gaussian function. Bayesian analyses are carried out, both for fusion and quasielastic scattering data, to optimally determine quadrupole and hexadecapole deformation parameters of ²⁸Si. The results suggest that extracted values are not free from ambiguities, thus necessitating utmost caution while extracting ground state deformation parameters following this method.