Sprecher
Beschreibung
Neutrinos in dense astrophysical environments play an important role in shaping the dynamics and nucleosynthesis of systems such as core-collapse supernovae and binary neutron star mergers. We have recently investigated collective neutrino-antineutrino pairing phenomena within an extended mean-field framework that incorporates neutrino-antineutrino pairing correlations [1]. Unlike conventional studies focusing on flavor conversion, our analysis emphasizes pairing conversion driven by collective pairing instabilities. Using toy models with discretized momentum modes, we study the conditions under which collective pairing conversions can occur in anisotropic neutrino media. We find that pairing instabilities emerge when the excessive pair-occupation number—defined as the sum of neutrino and antineutrino occupation numbers minus unity—changes sign across momentum space. In single-energy systems, the instability can trigger significant collective pairing conversions between different momentum modes. However, in multi-energy configurations, the overall amount of collective pairing conversions are generally suppressed because the instability only develops in limited energy bins and cannot coherently involve the entire neutrino ensemble. Our results motivate further studies to assess the relevance of neutrino-antineutrino pairing effects in realistic astrophysical and cosmological environments.
[1] S.-J. Huang, M.-R. Wu, arXiv:2604.25687.