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Autores principales: Astros, María Dias, Gráf, Lukáš, Vogl, Stefan
Formato: Preprint
Publicado: 2025
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Acceso en línea:https://arxiv.org/abs/2511.22638
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author Astros, María Dias
Gráf, Lukáš
Vogl, Stefan
author_facet Astros, María Dias
Gráf, Lukáš
Vogl, Stefan
contents Late decays of dark matter to a lighter, warm dark matter component are a known way to reduce the amplitude of the matter power spectrum on scales of $8$ Mpc. However, only very few particle physics models have been put forward that exhibit the required properties and allow to relate them to other observables. In this work, we investigate a model based on two interacting sterile neutrinos and a scalar singlet. The heavier of the neutrinos is produced in the early Universe by the interplay of oscillations and the new interactions in the dark sector and constitutes the dominant component of dark matter. If the Yukawa matrix that describes the interactions of the steriles with the scalar is not diagonal, the heavier state can decay to three light sterile neutrinos. In contrast to the usual scenario, this leads to an all massive final state without radiation-like particles. We identify the part of the parameter space where these decays can lead to a reduction of S$_8$ at a level that matches observations. We then confront this region with the requirements of reproducing the observed relic density, as well as existing constraints from X-ray searches and Lyman-$α$ forest data.
format Preprint
id arxiv_https___arxiv_org_abs_2511_22638
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Less structure on $8$ Mpc scales from decaying sterile neutrino dark matter
Astros, María Dias
Gráf, Lukáš
Vogl, Stefan
High Energy Physics - Phenomenology
Late decays of dark matter to a lighter, warm dark matter component are a known way to reduce the amplitude of the matter power spectrum on scales of $8$ Mpc. However, only very few particle physics models have been put forward that exhibit the required properties and allow to relate them to other observables. In this work, we investigate a model based on two interacting sterile neutrinos and a scalar singlet. The heavier of the neutrinos is produced in the early Universe by the interplay of oscillations and the new interactions in the dark sector and constitutes the dominant component of dark matter. If the Yukawa matrix that describes the interactions of the steriles with the scalar is not diagonal, the heavier state can decay to three light sterile neutrinos. In contrast to the usual scenario, this leads to an all massive final state without radiation-like particles. We identify the part of the parameter space where these decays can lead to a reduction of S$_8$ at a level that matches observations. We then confront this region with the requirements of reproducing the observed relic density, as well as existing constraints from X-ray searches and Lyman-$α$ forest data.
title Less structure on $8$ Mpc scales from decaying sterile neutrino dark matter
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2511.22638