Neutrino oscillations in dense neutrino media

by Sergio PASTOR (IFIC, Valencia)

Thursday 6 Feb 2003, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

In the early universe or in some regions of supernovae, the neutrino refractive index is dominated by the neutrinos themselves. Several previous studies found numerically that these self-interactions have the effect of coupling different neutrino modes in such a way as to synchronize the flavour oscillations which otherwise would depend on the energy of a given mode. We show a simple explanation for this baffling phenomenon in analogy to the weak-field Zeeman effect in atoms. As applications, we discuss flavour neutrino oscillations in the early universe with non-zero neutrino asymmetries and in the rarefied region just outside the nascent neutron star a few seconds after supernova bounce.