Fast collective neutrino oscillations inside the neutrino sphere in core-collapse supernovae

Abstract

Neutrinos are believed to have a key role in the explosion mechanism of core-collapse supernovae as they carry most of the energy released by the gravitational collapse of a massive star. If their flavor is converted fast inside the neutrino sphere, the supernova explosion may be influenced. This paper is reporting the results of the extended work of our previous paper. We perform a thorough survey of the ELN crossing in one of our self-consistent, realistic Boltzmann simulations in two spatial dimensions under axisymmetry for the existence of the crossings between ${\nu }_e$ and ${\bar{\nu }}_e$ angular distributions, or the electron lepton number (ELN) crossing. We report for the first time the positive detections deep inside the core of the massive star in the vicinity of neutrino sphere at $r$ $\approx$ 16 - 21 km. We find that low values of the electron fraction $Y_e$ produced by convective motions together with the appearance of light elements are critically important to give rise to the ELN crossing by enhancing the chemical potential difference between proton and neutron, and hence by mitigating the Fermi-degeneracy of ${\nu }_e$. Since the region of positive detection are sustained and, in fact, expanding with time, it may have an impact on the explosion of core-collapse supernovae, observational neutrino astronomy and nucleosynthesis of heavy nuclei.

12 pages, 12 figures, accepted for publication in PRD

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Cited by in corpus (8)

• Fast Neutrino Flavor Conversion Modes in Multidimensional Core-collapse Supernova Models: the Role of the Asymmetric Neutrino Distributions
• On the characteristics of fast neutrino flavor instabilities in three-dimensional core-collapse supernova models
• Collective fast neutrino flavor conversions in a 1D box: Initial condition and long-term evolution
• A change of direction in pairwise neutrino conversion physics: The effect of collisions
• Fast Neutrino Flavor Conversion at Late Time
• New method for detecting fast neutrino flavor conversions in core-collapse supernova models with two-moment neutrino transport
• Three-flavor collective neutrino conversions with multi-azimuthal-angle instability in an electron-capture supernova model
• Where, when and why: occurrence of fast-pairwise collective neutrino oscillation in three-dimensional core-collapse supernova models