Motor Modes as Dark Matter

In this work, we investigate the possibility that stable Kaluza-Klein (KK) particles fromthe motor dimension model [1] can constitute the dark matter in the Universe. Unlikestandard UED models with KK parity, our model lacks a Z2 symmetry, which drasticallychanges the production and stability scenario for KK particles. We consider two productionmechanisms: thermal freeze-out and gravitational freeze-in via the radion Φ. It is shownthat for certain model parameters (M1 ∼ 100 GeV, Φinf ∼ 4 Ч 10−16, λ ∼ 10−8) , themotor modes can give a relic density consistent with WMAP/Planck observations (ΩDMh2 =0.120±0.001) . The model predicts characteristic signatures for direct and indirect detection,including annihilation into two photons with a monochromatic line at Eγ = M1.