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Physical Review D 76 (2007) 125018
Decoherence in supernova neutrino transformations suppressed by deleptonization
A. Esteban-Pretel, S. Pastor, R. Tomas, G.G. Raffelt, G. Sigl1, 2

In the dense-neutrino region at 50-400 km above the neutrino sphere in a supernova, neutrino-neutrino interactions cause large flavor transformations. We study when the multi-angle nature of the neutrino trajectories leads to flavor decoherence between different angular modes. We consider a two-flavor mixing scenario between nu_e and another flavor nu_x and assume the usual hierarchy F(nu_e)>F{antinu_e)>F(nu_x)=F(antinu_x) for the number fluxes. We define epsilon=(F(nu_e)-F(antinu_e))/(F(antinu_e)-F(antinu_x)) as a measure for the deleptonization flux which is the one crucial parameter. The transition between the quasi single-angle behavior and multi-angle decoherence is abrupt as a function of epsilon. For typical choices of other parameters, multi-angle decoherence is suppressed for epsilon>0.3, but a much smaller asymmetry suffices if the neutrino mass hierarchy is normal and the mixing angle small. The critical epsilon depends logarithmically on the neutrino luminosity. In a realistic supernova scenario, the deleptonization flux is probably enough to suppress multi-angle decoherence.
1 :  APC - UMR 7164 - AstroParticule et Cosmologie
2 :  IAP - Institut d'Astrophysique de Paris
Physique/Astrophysique/Cosmologie et astrophysique extra-galactique

Planète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique

Physique/Physique des Hautes Energies - Phénoménologie

Planète et Univers/Astrophysique
Astrophysics – High Energy Physics – Phenomenology
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