Cannibalism's lingering imprint on the matter power spectrum

The early universe may have contained internally thermalized dark sectors that were decoupled from the Standard Model. In such scenarios, the relic dark thermal bath, composed of the lightest particle in the dark sector, can give rise to an epoch of early matter domination prior to Big Bang Nucleosy...

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Bibliographic Details
Published in:Journal of cosmology and astroparticle physics 2022-01, Vol.2022 (1), p.17
Main Authors: Erickcek, Adrienne L., Ralegankar, Pranjal, Shelton, Jessie
Format: Article
Language:English
Subjects:
Astronomical models
ASTRONOMY AND ASTROPHYSICS
Big bang cosmology
cosmological perturbation theory
Cosmology
cosmology connection
cosmology of theories beyond the SM
Dark matter
dark matter theory
Nuclear fusion
Nuclei (nuclear physics)
particle physics
particle physics - cosmology connection
Perturbation
Thermal baths
Universe
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Summary:The early universe may have contained internally thermalized dark sectors that were decoupled from the Standard Model. In such scenarios, the relic dark thermal bath, composed of the lightest particle in the dark sector, can give rise to an epoch of early matter domination prior to Big Bang Nucleosynthesis, which has a potentially observable impact on the smallest dark matter structures. This lightest dark particle can easily and generically have number-changing self-interactions that give rise to “cannibal” behavior. We consider cosmologies where an initially sub-dominant cannibal species comes to temporarily drive the expansion of the universe, and we provide a simple map between the particle properties of the cannibal species and the key features of the enhanced dark matter perturbation growth in such cosmologies. We further demonstrate that cannibal self-interactions can determine the small-scale cutoff in the matter power spectrum even when the cannibal self-interactions freeze out prior to cannibal domination.
ISSN:1475-7516
1475-7516
DOI:10.1088/1475-7516/2022/01/017