Triplet structure of nuclear scissors mode

Abstract: The fine structure of the scissors mode is investigated 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. Together with the conventional scissors mode two new modes arise due to spin degrees of freedom. They generate significant $M1$ strength below the conventional energy range. The results of calculations of scissors resonances in Rare Earths and Actinides by WFM and QPNM methods are compared with experimental data. A remarkable coherence of both methods together with experimental data is observed.