71 research outputs found
Neutrino propagation in an electron background with an inhomogeneous magnetic field
We study the electromagnetic coupling of a neutrino that propagates in a
two-stream electron background medium. Specifically, we calculate the
electromagnetic vertex function for a medium that consists of a \emph{normal}
electron background plus another electron \emph{stream} background that is
moving with a velocity four-vector relative to the normal background.
The results can be used as the basis for studying the neutrino electromagnetic
properties and various processes in such a medium. As an application, we
calculate the neutrino dispersion relation in the presence of an external
magnetic field (), focused in the case in which is inhomogeneous,
keeping only the terms of the lowest order in and linear in the
and its gradient. We show that the dispersion relation contains additional
anisotropic terms involving the derivatives of , such as the gradient
of , which involve the stream background
velocity, and a term of the form that can be
present in the absence of the stream background, in addition to a term of the
form and the well known term that
arises in the constant case. The derivative-dependent terms are even
under a transformation. As a result, in contrast to the latter two just
mentioned, they depend on the sum of the particle and antiparticle densities
and therefore can be non-zero in a -symmetric medium in which the particle
and antiparticle densities are equal.Comment: Title changes, 39 pages, 2 figure
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