Dark Matter from a Conformal Dark Sector

TL;DR

This paper explores a novel dark matter model where a conformal dark sector interacts with the Standard Model, leading to a predictive scenario where dark matter relic density depends on CFT data and is viable within observational constraints.

Contribution

It introduces a Conformal Freeze-In mechanism for dark matter production, linking relic density to CFT operator dimensions and demonstrating phenomenological viability.

Findings

Relic density determined by CFT operator dimensions.

Dark matter mass predicted in keV-MeV range.

Model consistent with observational constraints.

Abstract

We consider theories in which a dark sector is described by a Conformal Field Theory (CFT) over a broad range of energy scales. A coupling of the dark sector to the Standard Model breaks conformal invariance. While weak at high energies, the breaking grows in the infrared, and at a certain energy scale the theory enters a confined (hadronic) phase. One of the hadronic excitations can play the role of dark matter. We study a "Conformal Freeze-In" cosmological scenario, in which the dark sector is populated through its interactions with the SM at temperatures when it is conformal. In this scenario, the dark matter relic density is determined by the CFT data, such as the dimension of the CFT operator coupled to the Standard Model. We show that this simple and highly predictive model of dark matter is phenomenologically viable. The observed relic density is reproduced for a variety of SM operators ("portals") coupled to the CFT, and the resulting models are consistent with observational constraints. The mass of the COFI dark matter candidate is predicted to be in the keV-MeV range.