  Nuclear scissors modes are considered in the frame of Wigner function moments
method generalized to take into account spin degrees of freedom and pair
correlations simultaneously. A new source of nuclear magnetism, connected with
counter-rotation of spins up and down around the symmetry axis (hidden angular
momenta), is discovered. Its inclusion into the theory allows one to improve
substantially the agreement with experimental data in the description of
energies and transition probabilities of scissors modes in rare earth nuclei.
