Reanalysis of the process of the cascade gamma decay of compound state of $^{198}$Au

TL;DR

This paper reanalyzes gamma decay data of $^{198}$Au to investigate photon strength functions and level density, revealing step-like behaviors and challenging the presence of a pygmy resonance.

Contribution

It applies a reanalysis using the Dubna approach to clarify the nature of photon strength and level density in $^{198}$Au, providing new insights into nuclear structure.

Findings

Level density shows step-like behavior at low excitation energies.

Photon strength function peaks around 5 MeV, not indicating a pygmy resonance.

Level density below neutron binding energy also exhibits step-like features.

Abstract

To further study the "pygmy" resonance phenomena in the photon strength function, we reanalyzed the two-step cascade data for the target nucleus $^{197}$Au using the Dubna group approach. The range of obtained values allows for meaningful conclusions: the level density at low excitation energy shows a step-like behavior; the electric dipole photon strength function has a broad maximum around $E_{\gamma}=5$ MeV and is not typical of a "pygmy" resonance; the level density below $B_{n}$ also demonstrates step-like behavior.