Neutrinos as Dark Matter
Fuente:
arXiv
Gespeichert in:
| Hauptverfasser: | , , |
|---|---|
| Format: | Preprint |
| Veröffentlicht: |
2026
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1866914432822542336 |
|---|---|
| author | Cline, James M. Herrera, Gonzalo Roux, Jean-Samuel |
| author_facet | Cline, James M. Herrera, Gonzalo Roux, Jean-Samuel |
| contents | Active neutrinos in standard cosmology were ruled out as a dark matter candidate in the 1980's. The reason is twofold: they are too light to account for the observed energy density of dark matter in the Universe, and their relativistic nature would spoil structure formation. In this note we suggest that an enhanced density of cold Standard Model active neutrinos today could behave effectively as dark matter, avoiding constraints from recombination and structure formation. Such an enhancement could be produced, for instance, by late-time decays of a light scalar field that is not in thermal equilibrium with the plasma. This mechanism is testable through the detection of the Cosmic Neutrino Background (C$ν$B), which could have an average cosmological energy density a factor of $\sim 100-200$ times larger than expected in $Λ$CDM. The postulated light neutrinophilic scalar field may be observable, with Yukawa couplings in the range $y \sim 5 \times 10^{-16}-10^{-12}$. A scenario preferred by structure formation constraints is that the scalar is a Majoron, and the neutrinos have an inverted mass hierarchy. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2603_28859 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Neutrinos as Dark Matter Cline, James M. Herrera, Gonzalo Roux, Jean-Samuel High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics High Energy Astrophysical Phenomena Active neutrinos in standard cosmology were ruled out as a dark matter candidate in the 1980's. The reason is twofold: they are too light to account for the observed energy density of dark matter in the Universe, and their relativistic nature would spoil structure formation. In this note we suggest that an enhanced density of cold Standard Model active neutrinos today could behave effectively as dark matter, avoiding constraints from recombination and structure formation. Such an enhancement could be produced, for instance, by late-time decays of a light scalar field that is not in thermal equilibrium with the plasma. This mechanism is testable through the detection of the Cosmic Neutrino Background (C$ν$B), which could have an average cosmological energy density a factor of $\sim 100-200$ times larger than expected in $Λ$CDM. The postulated light neutrinophilic scalar field may be observable, with Yukawa couplings in the range $y \sim 5 \times 10^{-16}-10^{-12}$. A scenario preferred by structure formation constraints is that the scalar is a Majoron, and the neutrinos have an inverted mass hierarchy. |
| title | Neutrinos as Dark Matter |
| topic | High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2603.28859 |