Playing with lepton asymmetry at the resonant production of sterile neutrino dark matter

Fuente: arXiv
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Main Authors: Gorbunov, Dmitry, Kalashnikov, Dmitry, Krugan, George
Format: Preprint
Published: 2025
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author Gorbunov, Dmitry
Kalashnikov, Dmitry
Krugan, George
author_facet Gorbunov, Dmitry
Kalashnikov, Dmitry
Krugan, George
contents We examine the sterile neutrino dark matter production in the primordial plasma with lepton asymmetry unequally distributed over different neutrino flavors. We argue that with the specific flavor fractions, one can mitigate limits from the Big Bang Nucleosynthesis on the sterile-active neutrino mixing angle and sterile neutrino mass. It happens due to cancellation of the neutrino flavor asymmetries in active neutrino oscillations, which is more efficient in the case of inverse hierarchy of active neutrino masses and does not depend on the value of CP-phase. This finding opens a window of lower sterile-active mixing angles. Likewise, we show that, with lepton asymmetry disappearing from the plasma at certain intermediate stages of the sterile neutrino production, the spectrum of produced neutrinos becomes much colder, which weakens the limits on the model parameter space from observations of cosmic small-scale structures (Ly-$α$ forest, galaxy counts, etc.). This finding reopens the region of lighter sterile neutrinos. The new region may be explored with the next generation of X-ray telescopes searching for the inherent peak signature provided by the dark matter sterile neutrino radiative decays in the Galaxy.
format Preprint
id arxiv_https___arxiv_org_abs_2502_17374
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Playing with lepton asymmetry at the resonant production of sterile neutrino dark matter
Gorbunov, Dmitry
Kalashnikov, Dmitry
Krugan, George
High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
We examine the sterile neutrino dark matter production in the primordial plasma with lepton asymmetry unequally distributed over different neutrino flavors. We argue that with the specific flavor fractions, one can mitigate limits from the Big Bang Nucleosynthesis on the sterile-active neutrino mixing angle and sterile neutrino mass. It happens due to cancellation of the neutrino flavor asymmetries in active neutrino oscillations, which is more efficient in the case of inverse hierarchy of active neutrino masses and does not depend on the value of CP-phase. This finding opens a window of lower sterile-active mixing angles. Likewise, we show that, with lepton asymmetry disappearing from the plasma at certain intermediate stages of the sterile neutrino production, the spectrum of produced neutrinos becomes much colder, which weakens the limits on the model parameter space from observations of cosmic small-scale structures (Ly-$α$ forest, galaxy counts, etc.). This finding reopens the region of lighter sterile neutrinos. The new region may be explored with the next generation of X-ray telescopes searching for the inherent peak signature provided by the dark matter sterile neutrino radiative decays in the Galaxy.
title Playing with lepton asymmetry at the resonant production of sterile neutrino dark matter
topic High Energy Physics - Phenomenology
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2502.17374