Neutrino oscillations in moving and polarized matter under the influence of electromagnetic fields

Within the recently proposed Lorentz invariant formalism for description of neutrino spin evolution in presence of an arbitrary electromagnetic fields matter motion and polarization effects are considered. It is shown that in the case of matter moving with relativistic speed parallel to neutrino pro pagation, matter effects in neutrino spin (and also flavour) oscillations a re suppressed. In the case of relativistic motion of matter in the opposite direction in respect to neutrino propagation, sufficient increase of effec ts of matter in neutrino oscillations is predicted. These phenomena could h ave important consequences in different astrophysical environments. (C) 200 1 Published by Elsevier Science B.V.