Spectral representation of neutrino propagator in media and off-shell spin properties

Abstract

We construct a spectral representation of neutrino propagator in matter moving with constant velocity, or in constant homogenious magnetic field. In both cases there exists definite 4-axis $z$ of complete polarization, such that corresponding spin projectos commute with propagator. As a result, all eigenvalues of propagator and dispersion laws are classified accoding to spin projection on this axis.

Comments: 4 pages, Talk at 19th Lomonosov Conf. on Elem. Part. Physics (MSU, Moscow, August 22-28, 2019)