http://arxiv.org/abs/1711.07344
We show that in the Feebly Interacting Massive Particle (FIMP) model of Dark Matter (DM), one may express the inflationary energy scale $H_$ as a function of three otherwise unrelated quantities, the DM isocurvature perturbation amplitude, its mass and its self-coupling constant, independently of the tensor-to-scalar ratio. The FIMP model assumes that there exists a real scalar particle that alone constitutes the DM content of the Universe and couples to the Standard Model via a Higgs portal. We consider carefully the various astrophysical, cosmological and model constraints, accounting also for variations in inflationary dynamics and the reheating history, to derive a robust estimate for $H_$ that is confined to a relatively narrow range. We point out that, within the context of the FIMP DM model, one may thus determine $H_*$ reliably even in the absence of observable tensor perturbations.
K. Enqvist, R. Hardwick, T. Tenkanen, et. al.
Tue, 21 Nov 17
36/79
Comments: 25 pages, 11 figures