Spectator dark matter in nonstandard cosmologies

It has been shown that the observed dark matter (DM) abundance can be produced by amplification of quantum fluctuations of an energetically subdominant scalar field during inflation. In this paper, we study the robustness of this "spectator dark matter" scenario to changes in the expansion...

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Bibliographic Details
Published in:Physical review. D 2020-12, Vol.102 (12), Article 123534
Main Authors: Cosme, Catarina, Tenkanen, Tommi
Format: Article
Language:English
Subjects:
Dark matter
Expanding universe theory
Flux density
Perturbation
Scalars
Testability
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Summary:It has been shown that the observed dark matter (DM) abundance can be produced by amplification of quantum fluctuations of an energetically subdominant scalar field during inflation. In this paper, we study the robustness of this "spectator dark matter" scenario to changes in the expansion rate of the early Universe. Compared to the standard radiation-dominated (RD) scenario, two aspects will change: the DM energy density evolves differently as a function of time, and also the DM isocurvature perturbation spectrum will be different from the result in the RD case. These can impose sizeable changes to the values of model parameters which allow the field to constitute all DM while simultaneously satisfying all observational constraints. We study both free and self-interacting DM in scenarios with nonstandard expansion and quantify the changes to the cases with a standard cosmological history. We also discuss testability of the scenario through primordial DM isocurvature and non-Gaussianity.
ISSN:2470-0010
2470-0029
DOI:10.1103/PhysRevD.102.123534