Etudes des proprietes des neutrinos dans les contextes ...

tel-00450051, version 1 - 25 Jan 2010
Chapter 7
A dynamical collective
calculation of supernova neutrino
signals
Impressive progress has been achieved in the last few years in our understanding
of how neutrinos propagate in supernovae, fundamentally modifying the standard
MSW effect paradigm. This evolution is due to the substantial progress made
in the calculations which now include neutrino-neutrino interactions as we have
seen in chapter 5 and shock wave effects. We present here the first numerical
calculation in three flavors to include both the neutrino-neutrino interaction and
dynamic MSW effects using matched density profiles and correctly putting them
together using evolution operators rather than probabilities. We focus upon
results on the anti-neutrino time signals. Signatures pinpointing to the hierarchy
and possible θ13 values are shown, even for values beyond the proposed reach of
future experiments on Earth [68].
7.1 Introduction
7.1.1 A dynamic supernova density profile
Let us describe briefly the density profile when a moving shock is taken into account.
We work with the density profile obtained by hydrodynamical simulations
from [81] where all details of the model are given. We present here a brief visual
summary of what is done. We consider here a spherical symmetry, and therefore
use only a 1D density profile. Going to two dimensions will render the density
profile more complex and can lead to asphericities. On Fig.(7.1), one can see the
different characteristic feature of an exploding supernova. 1
1 Note that in this model the idea is to artificially deposit energy to mimick the neutrino
heating which will revive the stalling shock. Consequently, a forward shock develops.
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