Speed-up of neutrino transformations in a supernova environment

Abstract

When the neutral current neutrino-neutrino interaction is treated completely, rather than as an interaction among angle-averaged distributions, or as a set of flavor-diagonal effective potentials, the result can be flavor mixing at a speed orders of magnitude faster than that one would anticipate from the measured neutrino oscillation parameters. It is possible that the energy spectra of the three active species of neutrinos emerging from a supernova are nearly identical.Comment: 8 pages, 4 figure

Self-induced decoherence in dense neutrino gases

“…With hindsight this is probably the same "speed-up effect" discussed in Ref. [11]. However, the fast speed κ = √ 2ωµ is not introduced by the multi-angle effect as is perhaps suggested in Ref.…”

“…However, the fast speed κ = √ 2ωµ is not introduced by the multi-angle effect as is perhaps suggested in Ref. [11]. Rather, κ is the bipolar oscillation frequency that is inherent even in the isotropic system.…”

“…It was recently stressed, however, that this is not the complete story [11,24]. Perhaps the most interesting case for collective effects is provided by neutrinos * UMR 7164 (CNRS, Université Paris 7, CEA, Observatoire de Paris) streaming off a supernova core, a situation that is far from isotropic.…”

“…Therefore, if the energy spectrum is broad, the energy dependence of the oscillation frequency quickly leads to kinematical decoherence, i.e., along a neutrino beam the overall flavor content quickly approaches an average value. The situation changes radically when neutrinos themselves provide a significant refractive effect, leading to collective oscillation modes [1,2,3,4,5,6,7,8,9,10,11,12] that can be of practical interest in the early universe [13,14,15,16] or in core-collapse supernovae [17,18,19,20,21,22,23,24,25,26]. Defining the parameter…”

Neutrino–neutrino interactions and flavour mixing in dense matter

“…The effective Hamiltonian describing the propagation of neutrinos in a background of electrons is given by [29] …”