Criteria for the occurrence of Crossings Between the Angular Distributions of Electron Neutrinos and Antineutrinos in the Supernova Core. (arXiv:1904.07236v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Shalgar_S/0/1/0/all/0/1">Shashank Shalgar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tamborra_I/0/1/0/all/0/1">Irene Tamborra</a>
Neutrino fast pairwise conversions have been postulated to occur in the dense
core of a core-collapse supernova (SN), possibly having dramatic consequences
on the SN mechanism and the observable neutrino signal. One crucial condition
favoring pairwise conversions is the presence of crossings between the electron
neutrino and antineutrino angular distributions (i.e., electron neutrino lepton
number crossings, ELN crossings). A stationary and spherically symmetric SN
toy-model is constructed to reproduce the development of the neutrino angular
distributions in the dense SN core in the absence of perturbations induced by
hydrodynamical instabilities. By iteratively solving the neutrino Boltzmann
equations including the collisional term, our model predicts that ELN crossings
can develop only in the proximity of the decoupling region and for a shallow
radial evolution of the baryon density, when the electron neutrino and
antineutrino number densities are comparable. Such conditions are likely to
occur only in the late SN stages. Interestingly, flavor instabilities induced
by spatial or temporal perturbations are unlikely to generate ELN crossings
dynamically.
Neutrino fast pairwise conversions have been postulated to occur in the dense
core of a core-collapse supernova (SN), possibly having dramatic consequences
on the SN mechanism and the observable neutrino signal. One crucial condition
favoring pairwise conversions is the presence of crossings between the electron
neutrino and antineutrino angular distributions (i.e., electron neutrino lepton
number crossings, ELN crossings). A stationary and spherically symmetric SN
toy-model is constructed to reproduce the development of the neutrino angular
distributions in the dense SN core in the absence of perturbations induced by
hydrodynamical instabilities. By iteratively solving the neutrino Boltzmann
equations including the collisional term, our model predicts that ELN crossings
can develop only in the proximity of the decoupling region and for a shallow
radial evolution of the baryon density, when the electron neutrino and
antineutrino number densities are comparable. Such conditions are likely to
occur only in the late SN stages. Interestingly, flavor instabilities induced
by spatial or temporal perturbations are unlikely to generate ELN crossings
dynamically.
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