# Decoherence in supernova neutrino transformations suppressed by deleptonization

1 APC - THEORIE
IAP - Institut d'Astrophysique de Paris, APC - UMR 7164 - AstroParticule et Cosmologie
Abstract : 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.
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Journal articles
Physical Review D, American Physical Society, 2007, 76, pp.125018. <10.1103/PhysRevD.76.125018>
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http://hal.in2p3.fr/in2p3-00161087
Contributor : Simone Lantz <>
Submitted on : Monday, July 9, 2007 - 5:25:35 PM
Last modification on : Friday, September 11, 2015 - 9:50:17 AM

### Citation

A. Esteban-Pretel, S. Pastor, R. Tomas, G.G. Raffelt, G. Sigl. Decoherence in supernova neutrino transformations suppressed by deleptonization. Physical Review D, American Physical Society, 2007, 76, pp.125018. <10.1103/PhysRevD.76.125018>. <in2p3-00161087>

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