Collective neutrino-antineutrino pair oscillations

Fuente: arXiv
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Main Authors: Huang, Shih-Jie, Wu, Meng-Ru
Format: Preprint
Published: 2026
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author Huang, Shih-Jie
Wu, Meng-Ru
author_facet Huang, Shih-Jie
Wu, Meng-Ru
contents In dense neutrino gas, pairing correlations between neutrinos and antineutrinos with opposite momenta can be nonzero in generalized neutrino quantum kinetic equations at the mean-field level. In this Letter, we investigate for the first time the condition under which collective neutrino-antineutrino ($ν\barν$) pairing instabilities can occur, using simplified toy models consisting of discretized $ν\barν$ pairs in a homogeneous neutrino gas. We find that, in ansiotropic systems, $ν\barν$ pairing instabilities generally emerge when the phase space distribution of the excessive pair-occupation number, defined as the sum of the neutrino and antineutrino occupation numbers of a pair minus 1, changes signs. The associated instability growth rate is set by the forward scattering potential and is comparable to that of collective fast neutrino flavor instabilities. The instabilities can result in pair conversions of $ν\barν$ occupation numbers between different momentum modes. Our results motivate further studies to assess the relevance of $ν\barν$ pairing effects in realistic astrophysical and cosmological environments.
format Preprint
id arxiv_https___arxiv_org_abs_2604_25687
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Collective neutrino-antineutrino pair oscillations
Huang, Shih-Jie
Wu, Meng-Ru
High Energy Physics - Phenomenology
High Energy Astrophysical Phenomena
In dense neutrino gas, pairing correlations between neutrinos and antineutrinos with opposite momenta can be nonzero in generalized neutrino quantum kinetic equations at the mean-field level. In this Letter, we investigate for the first time the condition under which collective neutrino-antineutrino ($ν\barν$) pairing instabilities can occur, using simplified toy models consisting of discretized $ν\barν$ pairs in a homogeneous neutrino gas. We find that, in ansiotropic systems, $ν\barν$ pairing instabilities generally emerge when the phase space distribution of the excessive pair-occupation number, defined as the sum of the neutrino and antineutrino occupation numbers of a pair minus 1, changes signs. The associated instability growth rate is set by the forward scattering potential and is comparable to that of collective fast neutrino flavor instabilities. The instabilities can result in pair conversions of $ν\barν$ occupation numbers between different momentum modes. Our results motivate further studies to assess the relevance of $ν\barν$ pairing effects in realistic astrophysical and cosmological environments.
title Collective neutrino-antineutrino pair oscillations
topic High Energy Physics - Phenomenology
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2604.25687