Universal Extra Dimensions at the e − e − Colliders ∗

Universal Extra Dimensions (UEDs) with compactification radius near the TeV scale provide interesting phenomenology at future colliders. The collider signals of the first Kaluza-Klein (KK) level are very similar to those of a supersymmetric model with a nearly degenerate superpartner spectrum. The heavier first level KK states cascade decay to the lightest KK particles (LKP), which is neutral and stable because of KKparity. The signatures involve missing energy and relatively soft jets and leptons which can be difficult for detection. The KK electron signal in ee collisions is free from the problematic two photon background therefore provides a unique opportunity for a detailed studies of the KK electrons in the Universal Extra Dimension scenario. ∗ Talk presented at the 4th International Workshop on Electron-Electron Interactions at TeV Energies, University of California, Santa Cruz, Dec.7-9, 2001 Email: [email protected]