Dark Matter Casts Light on the Early Universe

TL;DR

This paper demonstrates how dark matter density measurements, combined with BSM physics parameters, can reveal details about the universe's evolution before BBN, especially in models with scalar fields and quintessence.

Contribution

It introduces a method to use CDM density to constrain early universe models with scalar fields and quintessence, extending understanding beyond standard cosmology.

Findings

CDM density constrains initial scalar field density and reheating temperature.

Decays of scalar fields into BSM particles can be constrained.

Early evolution of quintessence fields can be inferred from CDM data.

Abstract

We show how knowledge of the cold dark matter (CDM) density can be used, in conjunction with measurements of the parameters of a scenario for beyond the Standard Model (BSM) physics, to provide information about the evolution of the Universe before Big Bang Nucleosynthesis (BBN). As examples of non-standard evolution, we consider models with a scalar field that may decay into BSM particles, and quintessence models. We illustrate our calculations using various supersymmetric models as representatives of classes of BSM scenarios in which the CDM density is either larger or smaller than the observed density when the early Universe is assumed to be radiation-dominated. In the case of a decaying scalar field, we show how the CDM density can constrain the initial scalar density and the reheating temperature after it decays in BSM scenarios that would yield overdense dark matter in standard radiation-dominated cosmology, and how the decays of the scalar field into BSM particles can be constrained in scenarios that would otherwise yield underdense CDM. We also show how the early evolution of the quintessence field can be constrained in BSM scenarios.