The energy dependence of the electric dipole strength in heavy nuclei

TL;DR

This study examines how well Lorentzian models fit the photon strength in heavy nuclei across a range of energies, revealing that with deformation effects considered, the models are accurate down to about 5 MeV.

Contribution

It demonstrates that Lorentzian fits to photo-neutron data accurately describe photon strength below the neutron threshold when deformation effects are included.

Findings

Lorentzian models fit photon strength well down to 5 MeV

Deformation effects eliminate the need to differentiate nuclei types

Photon scattering data supports model accuracy across various nuclei

Abstract

On the basis of new photon scattering measurements and a reevaluation of average neutron resonance capture data we investigate how well Lorentzians adjusted to photo-neutron data in the giant dipole resonances give a good description of the photon strength also below the neutron threshold. If deformation effects are properly taken into account this is verified down to about 5 MeV for various nuclei with A>80 such that the previously employed differentiation between deformed and non-deformed nuclei is no longer necessary.