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Free keywords:
High Energy Physics - Phenomenology, hep-ph, Astrophysics, Solar and Stellar Astrophysics, astro-ph.SR,High Energy Physics - Experiment, hep-ex
Abstract:
In dense neutrino backgrounds present in supernovae and in the early
Universe, neutrino oscillations may exhibit complex collective phenomena, such
as synchronized oscillations, bipolar oscillations and spectral splits and
swaps. In this Letter we consider for the first time the effects of decoherence
by wave packet separation on these phenomena. We derive the evolution equations
that govern neutrino oscillations in a dense medium in the presence of
decoherence and consider the evolution of several simple neutrino systems in
detail. We show that decoherence may modify the oscillation pattern
significantly and lead to qualitatively new effects. In particular, contrary to
the no-decoherence case, strong flavor conversion becomes possible even in the
case of constant or nearly constant density of the neutrino background.
