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Main Authors: Padilla-Gay, Ian, Chen, Heng-Hao, Abbar, Sajad, Wu, Meng-Ru, Xiong, Zewei
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2505.11588
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author Padilla-Gay, Ian
Chen, Heng-Hao
Abbar, Sajad
Wu, Meng-Ru
Xiong, Zewei
author_facet Padilla-Gay, Ian
Chen, Heng-Hao
Abbar, Sajad
Wu, Meng-Ru
Xiong, Zewei
contents Neutrinos experience collective flavor conversion in extreme astrophysical environments such as core-collapse supernovae (CCSNe). One manifestation of collective conversion is slow flavor conversion (SFC), which has recently attracted renewed interest owing to its ubiquity across different regions of the supernova environment. In this study, we systematically examine the evolution of kinematic decoherence in a dense neutrino gas undergoing SFC, considering lepton number asymmetries as large as $30\%$. Our findings show that the neutrino gas asymptotically evolves toward a generic state of coarse-grained flavor equilibration which is constrained by approximate lepton number conservation. The equilibration occurs within a few factors of the inverse vacuum oscillation frequency, $ω^{-1}$, which corresponds to (anti)neutrinos reaching near flavor equipartition after a few kilometers for typical supernova neutrino energies. Notably, the quasi-steady state of the neutrino number densities can be quantitatively described by the neutrino-antineutrino number density ratio $n_{\barν_e}/n_{ν_e}$ alone. Such a simple estimation opens new opportunities for incorporating SFC into CCSN simulations, particularly in regions where SFC develops on scales much shorter than those of collisions.
format Preprint
id arxiv_https___arxiv_org_abs_2505_11588
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Flavor Equilibration of Supernova Neutrinos: Exploring the Dynamics of Slow Modes
Padilla-Gay, Ian
Chen, Heng-Hao
Abbar, Sajad
Wu, Meng-Ru
Xiong, Zewei
High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
Neutrinos experience collective flavor conversion in extreme astrophysical environments such as core-collapse supernovae (CCSNe). One manifestation of collective conversion is slow flavor conversion (SFC), which has recently attracted renewed interest owing to its ubiquity across different regions of the supernova environment. In this study, we systematically examine the evolution of kinematic decoherence in a dense neutrino gas undergoing SFC, considering lepton number asymmetries as large as $30\%$. Our findings show that the neutrino gas asymptotically evolves toward a generic state of coarse-grained flavor equilibration which is constrained by approximate lepton number conservation. The equilibration occurs within a few factors of the inverse vacuum oscillation frequency, $ω^{-1}$, which corresponds to (anti)neutrinos reaching near flavor equipartition after a few kilometers for typical supernova neutrino energies. Notably, the quasi-steady state of the neutrino number densities can be quantitatively described by the neutrino-antineutrino number density ratio $n_{\barν_e}/n_{ν_e}$ alone. Such a simple estimation opens new opportunities for incorporating SFC into CCSN simulations, particularly in regions where SFC develops on scales much shorter than those of collisions.
title Flavor Equilibration of Supernova Neutrinos: Exploring the Dynamics of Slow Modes
topic High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2505.11588