Аннотация:
Generally speaking, the existence of
a superluminal neutrino can be attributed either
to re-entrant Lorentz violation at ultralow energy
from intrinsic Lorentz violation at ultrahigh energy
or to spontaneous breaking of fundamental Lorentz invariance
(possibly by the formation of a fermionic condensate).
Re-entrant Lorentz violation in the neutrino sector has been
discussed elsewhere. Here, the focus is on mechanisms
of spontaneous symmetry breaking.