Probing universal extra dimension at the International Linear Collider

In the context of an universal extra-dimensional scenario, we consider production of the first Kaluza-Klein electron positron pair in an e+e− collider as a case-study for the future International Linear Collider. The Kaluza-Klein electron decays into a nearly degenerate Kaluza-Klein photon and a standard electron, the former carrying away missing energy. The Kaluza-Klein electron and photon states are heavy with their masses around the inverse radius of compactification, and their splitting is controlled by radiative corrections originating from bulk and brane-localised interactions. We look for the signal event e+e−+ large missing energy for s=1 TeV and observe that with a few hundred fb−1 luminosity the signal will be readily detectable over the standard model background. We comment on how this signal may be distinguished from similar events from other new physics.