Origins of Hidden Sector Dark Matter I: Cosmology

TL;DR

This paper systematically explores how dark matter originating from a hidden sector can be produced through various mechanisms like Freeze-Out and Freeze-In, linking cosmological models with potential collider signatures.

Contribution

It classifies all possible weak-scale dark matter origins in hidden sectors and connects these mechanisms with measurable collider parameters.

Findings

Dark matter can originate via a limited set of mechanisms.

Each mechanism corresponds to specific lifetime and cross-section windows.

LHC measurements could potentially identify the dark matter origin.

Abstract

We present a systematic cosmological study of a universe in which the visible sector is coupled, albeit very weakly, to a hidden sector comprised of its own set of particles and interactions. Assuming that dark matter (DM) resides in the hidden sector and is charged under a stabilizing symmetry shared by both sectors, we determine all possible origins of weak-scale DM allowed within this broad framework. We show that DM can arise only through a handful of mechanisms, lending particular focus to Freeze-Out and Decay and Freeze-In, as well as their variations involving late time re-annihilations of DM and DM particle anti-particle asymmetries. Much like standard Freeze-Out, where the abundance of DM depends only on the annihilation cross-section of the DM particle, these mechanisms depend only on a very small subset of physical parameters, many of which may be measured directly at the LHC. In particular, we show that each DM production mechanism is associated with a distinctive window in lifetimes and cross-sections for particles which may be produced in the near future. We evaluate prospects for employing the LHC to definitively reconstruct the origin of DM in a companion paper.