Little composite dark matter

TL;DR

This paper explores a composite electroweak singlet dark matter candidate within an extended Littlest Higgs model, demonstrating it can match observed relic abundance and evade detection constraints through its unique composite nature and Higgs portal interactions.

Contribution

It introduces a novel composite electroweak singlet dark matter model based on the Littlest Higgs with T-parity, analyzing its phenomenology and experimental viability.

Findings

Viable parameter space consistent with relic abundance and experimental constraints.

Distinct LHC signatures involving third-generation quarks and Higgs bosons.

The dark matter candidate interacts weakly via Higgs portal, evading direct detection.

Abstract

We examine the dark matter phenomenology of a composite electroweak singlet state. This singlet belongs to the Goldstone sector of a well-motivated extension of the Littlest Higgs with $T$-parity. A viable parameter space, consistent with the observed dark matter relic abundance as well as with the various collider, electroweak precision and dark matter direct detection experimental constraints is found for this scenario. $T$-parity implies a rich LHC phenomenology, which forms an interesting interplay between conventional natural SUSY type of signals involving third generation quarks and missing energy, from stop-like particle production and decay, and composite Higgs type of signals involving third generation quarks associated with Higgs and electroweak gauge boson, from vector-like top-partners production and decay. The composite features of the dark matter phenomenology allows the composite singlet the produce the correct relic abundance while interacting weakly with the Higgs via the usual Higgs portal coupling $\lambda_{\text{DM}} \sim O(1\%)$, thus evading direct detection.