On the Microscopic Level Density Models for Nuclei Near Z=28 Shell Closure

TL;DR

This study evaluates various level density models for nuclei near Z=28, using experimental proton decay spectra and statistical analysis, concluding that the Gogny HFB microscopic model provides the most accurate predictions.

Contribution

It introduces a variance minimization approach to assess level density models, identifying the Gogny HFB microscopic model as the most accurate for nuclei near Z=28.

Findings

Gogny HFB microscopic model best reproduces experimental spectra.

Variance minimization effectively compares level density models.

Microscopic models outperform phenomenological ones in this context.

Abstract

A comprehensive test of level density models for explaining the decay of excited compound nuclei, 54 Mn, 56 Fe, 58 Co, 60 Ni, 61 Ni and 63 Cu, in the energy range of 28 - 36 MeV has been performed. The compound nuclei of interest in the desired ranges are populated using 6 Li based transfer reactions. The proton decay spectrum for each excitation energy bins has been measured. The measured proton spectrum has been reproduced using statistical model calculations with different level density models. A variance minimised approach has been employed for analysing the prediction capability of different level density models. This approach has been converged to Gogny Hartree-Fock-Bogoliubov(HFB) microscopic level density model and which is attributed as the most accurate model for the desired nuclei.