Neutrino spin operator and dispersion in moving matter

Abstract

We found the spin integral of motion for neutrinos propagating in moving and polarized matter. Contrary to all previous studies this is the exact spin operator commuting with the Hamiltonian for a neutrino in matter which moves in an arbitrary direction relative to the direction of neutrino propagation. The operator obtained opens up the possibility of consistent classification of neutrino states in such a medium and, as a consequence, a systematic description of the related physical phenomena. Using the operator, we obtain a dispersion relation for neutrinos in arbitrary moving matter and consider its particular cases.