Composite Scalar Dark Matter

TL;DR

This paper proposes that a light composite scalar, emerging as a pseudo Nambu-Goldstone boson from a strongly-coupled sector, can serve as dark matter, with specific parameter regions satisfying relic density and experimental constraints.

Contribution

It introduces a model where a composite scalar pNGB acts as dark matter, linking Higgs compositeness with dark matter phenomenology and exploring its detection prospects.

Findings

DM mass around 50-70 GeV with Higgs resonance annihilation

DM mass range 100-500 GeV with derivative Higgs interaction

Potential for Higgs invisible decay to DM particles

Abstract

We show that the dark matter (DM) could be a light composite scalar $\eta$, emerging from a TeV-scale strongly-coupled sector as a pseudo Nambu-Goldstone boson (pNGB). Such state arises naturally in scenarios where the Higgs is also a composite pNGB, as in $O(6)/O(5)$ models, which are particularly predictive, since the low-energy interactions of $\eta$ are determined by symmetry considerations. We identify the region of parameters where $\eta$ has the required DM relic density, satisfying at the same time the constraints from Higgs searches at the LHC, as well as DM direct searches. Compositeness, in addition to justify the lightness of the scalars, can enhance the DM scattering rates and lead to an excellent discovery prospect for the near future. For a Higgs mass $m_h\simeq 125$ GeV and a pNGB characteristic scale $f \lesssim 1$ TeV, we find that the DM mass is either $m_\eta \simeq 50-70$ GeV, with DM annihilations driven by the Higgs resonance, or in the range 100-500 GeV, where the DM derivative interaction with the Higgs becomes dominant. In the former case the invisible Higgs decay to two DM particles could weaken the LHC Higgs signal.