Vector Dark Matter from the 5-Dimensional Representation of $SU(2)_{L}$

Abstract: The introduction of electroweak multiplets that transform under any representation of the standard $SU(2)_L$ gauge group suggests the existence of electrically neutral stable particles capable of serving as cold dark matter in the $\Lambda$CDM cosmological model. This paradigm, known as minimal dark matter, has primarily focused on spin-$0$ and spin-$1/2$ particles. We extend this study to the spin-1 case using the 5-dimensional real representation. We address unitarity concerns arising from the model's interactions with electroweak and Higgs fields of the Standard Model, investigating implications for dark matter relic density, direct and indirect detection, including non-perturbative Sommerfeld enhancement for the latter. Collider signatures of the proposed model are also examined. Our findings suggest that the model remains consistent with experimental constraints, particularly for dark matter masses on the order of dozens of TeV, and could potentially be tested using $\gamma$-ray observatories such as CTA.