Neutrino flavor transformation with moments: application to fast flavor instabilities in neutron star mergers

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.

Authors

Julien Froustey, University of California Berkeley
Sherwood Richers, University of Tennessee
Evan Grohs, North Carolina State University
Samuel Flynn, North Carolina State University
Francois Foucart, University of New Hampshire, DurhamFollow
Jim Kneller, North Carolina State University
Gail C. Mclaughlin, North Carolina State University

Abstract

Neutrino evolution, of great importance in environments such as neutron star mergers (NSMs) because of their impact on explosive nucleosynthesis, is still poorly understood due to the high complexity and variety of possible flavor conversion mechanisms. In this study, we focus on so-called "fast flavor oscillations", which can occur on timescales of nanoseconds and are connected to the existence of a crossing between the angular distributions of electron (anti)neutrinos. Based on the neutrino radiation field drawn from a three dimensional neutron star merger simulation, we use an extension of the two-moment formalism of neutrino quantum kinetics, and perform a linear stability analysis to determine the characteristics of fast flavor instabilities across the simulation. We compare the results to local (centimeter-scale) three-dimensional two-flavor simulations using either a moment method or a particle-in-cell architecture. We get generally good agreement in the instability growth rate and typical instability lengthscale, although the imperfections of the closure used in moment methods remain to be better understood.

Department

Physics

Publication Date

2-14-2024

Journal Title

Proceedings of XVIII International Conference on Topics in Astroparticle and Underground Physics — PoS(TAUP2023)

Publisher

Sissa Medialab

Digital Object Identifier (DOI)

https://dx.doi.org/10.22323/1.441.0341

Document Type

Conference Proceeding

Recommended Citation

Julien Froustey et al., “Neutrino Flavor Transformation with Moments: Application to Fast Flavor Instabilities in Neutron Star Mergers,” in Proceedings of XVIII International Conference on Topics in Astroparticle and Underground Physics — PoS(TAUP2023), vol. 441 (SISSA Medialab, 2024), 341, accessed June 12, 2025, https://pos.sissa.it/441/341.

Comments

This is an open access article published by Sissa Medialab in Proceedings of XVIII International Conference on Topics in Astroparticle and Underground Physics — PoS(TAUP2023) in 2024, available online: https://dx.doi.org/10.22323/1.441.0341