Inflationary Imprints on Dark Matter

TL;DR

This paper explores how the inflationary scale influences dark matter abundance in models with scalar fields coupled to the Higgs, revealing constraints on parameters to prevent overproduction of dark matter.

Contribution

It demonstrates the relationship between inflationary scale and dark matter relic density in Higgs-portal models with scalar singlets, providing parameter constraints.

Findings

Dark matter relic density depends on the inflationary scale.

For H ~ 10^{10} GeV, scalar coupling and mass must be within specific ranges.

Weakly coupled scalars can lead to dark matter overproduction if not constrained.

Abstract

We show that dark matter abundance and the inflationary scale $H$ could be intimately related. Standard Model extensions with Higgs mediated couplings to new physics typically contain extra scalars displaced from vacuum during inflation. If their coupling to Standard Model is weak, they will not thermalize and may easily constitute too much dark matter reminiscent to the moduli problem. As an example we consider Standard Model extended by a $Z_2$ symmetric singlet $s$ coupled to the Standard Model Higgs $\Phi$ via $\lambda \Phi^{\dag}\Phi s^2$. Dark matter relic density is generated non-thermally for $\lambda \lesssim 10^{-7}$. We show that the dark matter yield crucially depends on the inflationary scale. For $H\sim 10^{10}$ GeV we find that the singlet self-coupling and mass should lie in the regime $\lambda_{\rm s}\gtrsim 10^{-9}$ and $m_{\rm s}\lesssim 50$ GeV to avoid dark matter overproduction.