Nuclear reactions as a tool to study the microscopic structure of pygmy and giant resonances

Extreme Light Infrastructure (ELI-NP), Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH), Str. Reactorului No. 30, 077125 Bucharest-Mǎgurele, Romania

^* e-mail: nadia.tsoneva@eli-np.ro

Published online: 14 March 2024

Abstract

An advanced microscopic approach based on energy-density functional theory and the quasiparticle-phonon model has been used to study nuclear excitations up to giant dipole resonance energies. In addition, our nuclear structure model has been extended to include reaction theory. The theoretical spectral distributions compared with experimental data performed with different probes and techniques are able to provide us with information about the microscopic structure of the pygmy dipole resonance as well as its collectivity. Evaluations of electric dipole (E1) transition strengths and branching ratios at low energy reveal different properties of the nuclear excitations and the effect of quasi-continuum coupling. The present studies will support above-neutronthreshold γ experiments at ELI-NP targeting γ decays of giant and pygmy resonances, as well as studies on multi-step γ decays by low-lying states.