“…In this section, we consider spin oscillations of Dirac neutrinos, caused not only by the interaction with polarized medium, but also by the "direct" interaction of the neutrino magnetic moment with the magnetic field. Spin oscillations caused by the magnetic moment (without taking into account the matter polarization) have been considered in a number of papers, see, for instance 5 , [5,11,12,43,46,62,63] (a more complete list can be found in [1]). The corresponding contribution to the effective Hamiltonian in Eq.…”