https://doi.org/10.1140/epjs/s11734-024-01122-5
Regular Article
Realization of self-interacting freeze-in dark matter
1
Department of Physics, Indian Institute of Technology Kanpur, 208016, Kanpur, India
2
Theoretical Physics Division, Physical Research Laboratory, 380009, Ahmedabad, Gujarat, India
3
School of Physical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S.C. Mullick Road, 700032, Kolkata, India
4
Institute of Physics, Sachivalaya Marg, 751005, Bhubaneswar, Odisha, India
Received:
20
September
2023
Accepted:
14
February
2024
Published online:
5
March
2024
We explore the freeze-in production of dark matter in the singlet–doublet model where the dark matter is the lightest admixture of the neutral components of 
vector doublet and singlet fermion. Here, the scalar sector is extended by a MeV scalar mediating the self-interaction of the fermion dark matter, which solves the small-scale anomaly of the Universe. The scalar particle is stable and contributes to the relic density of the dark matter. Self-interacting dark matter scenario demands large interaction between the dark particles, which makes this sector strongly coupled. In this case, thermal equilibrium occurs in the dark sector after the freeze-in, and the relic abundance of the fermion dark matter gets suppressed in the radiation-dominated early Universe. However, the non-standard cosmological evolution in the early Universe helped the fermion dark matter to achieve almost whole contribution towards the observed relic.
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© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
