Gravity-mediated Dark Matter in Clockwork/Linear Dilaton Extra-Dimensions

TL;DR

This paper explores the possibility that dark matter interacts gravitationally with Standard Model particles within a five-dimensional Clockwork/Linear Dilaton framework, analyzing relic abundance and experimental constraints for various dark matter spins.

Contribution

It is the first detailed study of gravitational dark matter interactions in a Clockwork/Linear Dilaton extra-dimensional model, including annihilation channels and relic abundance.

Findings

Dark matter with mass 1-15 TeV can achieve observed relic abundance.

Relic abundance is compatible with LHC constraints across a range of 5D gravitational scales.

Results are independent of the dark matter particle's spin.

Abstract

We study for the first time the possibility that Dark Matter (represented by particles with spin $0,1/2$ or $1$) interacts gravitationally with Standard Model particles in an extra-dimensional Clockwork/Linear Dilaton model. We assume that both, the Dark Matter and the Standard Model, are localized in the IR-brane and only interact via gravitational mediators, namely the Kaluza-Klein (KK) graviton and the radion/KK-dilaton modes. We analyse in detail the Dark Matter annihilation channel into Standard Model particles and into two on-shell Kaluza-Klein towers (either two KK-gravitons, or two radion/KK-dilatons, or one of each), finding that it is possible to obtain the observed relic abundance via thermal freeze-out for Dark Matter masses in the range $m_{\rm DM} \in [1, 15]$ TeV for a 5-dimensional gravitational scale $M_5$ ranging from 5 to a few hundreds of TeV, even after taking into account the bounds from LHC Run II and irrespectively of the DM particle spin.