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arXiv · 2602.17821

Ly{\alpha} forest bounds on sterile neutrino production via neutrino self-interactions

Priyank Parashari·Vera Gluscevic·Yue Zhang·Simeon Bird·Mikhail M. Ivanov·Adam He
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Abstract

Sterile neutrinos in the keV mass range have long been considered a well-motivated dark matter (DM) candidate. In this work, we explore a sterile neutrino production mechanism through active neutrino self-interactions in the early universe, assuming that they constitute the full DM abundance. We implement a self-consistent treatment of the sterile-neutrino free streaming and the active-neutrino self-interactions on structure formation, which yield a unique scale-dependent modification to the linear matter power spectrum. We then set bounds on this scenario using a combination of the cosmic microwave background and Ly$\alpha$ forest constraints. Specifically, we utilize the two recent likelihoods derived from eBOSS data: (i) an effective field theory (EFT) based full-shape likelihood and (ii) a compressed likelihood obtained from the PRIYA-simulation emulator. We produce some of the most stringent observational constraints to date on sterile neutrino DM, comparable to the bounds from the most stringent laboratory constraints.

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Priyank Parashari, Vera Gluscevic, Yue Zhang, Simeon Bird, Mikhail M. Ivanov, Adam He. 2026-02-19. Ly{\alpha} forest bounds on sterile neutrino production via neutrino self-interactions. https://arxiv.org/abs/2602.17821

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