# Electroweak Kaluza-Klein Dark Matter

## TL;DR

This paper explores non-minimal universal extra dimension models where electroweak Kaluza-Klein particles serve as dark matter candidates, analyzing their phenomenology and experimental constraints to determine their viable mass range.

## Contribution

It introduces non-minimal UED models with boundary localized kinetic terms, revealing richer phenomenology and higher possible dark matter masses compared to minimal models.

## Key findings

- Electroweak Kaluza-Klein dark matter can reach masses up to 2.4 TeV.
- Non-minimal UED models exhibit complex mixing among KK excitations.
- Experimental constraints limit the dark matter mass to below 2.4 TeV.

## Abstract

In models with universal extra dimensions (UED), the lightest Kaluza-Klein excitation of neutral electroweak gauge bosons is a stable, weakly interacting massive particle and thus is a candidate for dark matter thanks to Kaluza-Klein parity. We examine concrete model realizations of such dark matter in the context of non-minimal UED extensions. The boundary localized kinetic terms for the electroweak gauge bosons lead to a non-trivial mixing among the first Kaluza-Klein excitations of the ${\rm SU}(2)_W$ and ${\rm U}(1)_Y$ gauge bosons and the resultant low energy phenomenology is rich. We investigate implications of various experiments including low energy electroweak precision measurements, direct and indirect detection of dark matter particles and direct collider searches at the LHC. Notably, we show that the electroweak Kaluza-Klein dark matter can be as heavy as 2.4 TeV, which is significantly higher than $1.3$ TeV as is indicated as an upper bound in the minimal UED model.