Scissors mode in transuranium elements

TL;DR

This paper investigates the scissors mode in transuranium elements using TDHFB and Wigner Function Moments methods, predicting a three-branch splitting and aligning well with recent experimental data, advancing understanding of nuclear excitations.

Contribution

It introduces a novel prediction of a three-branch splitting of the scissors mode due to spin effects in transuranium nuclei using TDHFB and WFM methods.

Findings

Predicted splitting of scissors mode into three branches.

Good agreement of energy centroid and $M1$ strength with experimental data.

Enhanced understanding of the double-humped structure in actinide spectra.

Abstract

The scissors mode is investigated in the actinides region, including even-even superheavy nuclei up to $^{256}$No, within the Time Dependent Hartree-Fock-Bogoliubov (TDHFB) approach. The solution of TDHFB equations by the Wigner Function Moments (WFM) method predicts a splitting of the scissors mode into three intermingled branches due to spin degrees of freedom. Both the calculated energy centroid and integrated $M1$ strength in $^{254}$No are in good agreement with the results of recent measurements performed by the Oslo method. The energy centroids and summed $B(M1)$ values for others transuranium nuclides are predicted. The calculations are performed also for $^{232}$Th and $^{236,238}$U isotopes using an updated compilation of deformation parameters. The results are compared with that obtained previously by WFM theory and with the latest experimental data. Progress has been achieved in theoretical understanding of the origins of double-humped structure of scissors spectrum observed in the Actinides.