Massive Dirac neutrinos in a background electromagnetic field

We investigate the propagation of a massive Dirac neutrino νe in a background electromagnetic field Fμλ. In particular we have obtained exact solutions for the Dirac-Schwinger equation with the self-energy operator of the neutrino which involves the effective electron and W-boson propagators allowing for interactions of these particles with an intense electromagnetic background. In the framework of the approach described above, we analyze the dispersion relation for the neutrino and calculate the effects induced by the external field. For example, in the massless case we obtain the following shift of the pole in the neutrino propagator: pμpμ + (g2e26π2MW4)[ln(MWme) + 38]pμFμλFλσpσ = 0. The external field impact on the dipole magnetic moment μν of the neutrino is also considered. We find that under certain conditions the magnitude of the static magnetic moment μ0=(3φ216φ2)GFemv can be enhanced by the electromagnetic field. However this effect is very small: μνμo = 1.016148. We also demonstrate the possibility of non-perturbative contributions being non-linear in Fμλ to influence spin precession phenomena. Some applications of these results to astrophysics and cosmology are discussed.