Spin-isospin structure of the nuclear scissors mode

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 quasiparticle-phonon nuclear model methods are compared with experimental data. A remarkable coherence of both methods together with experimental data is observed.