Kaluza-Klein dark matter, electrons and gamma-ray telescopes

Kaluza - Klein dark matter particles can annihilate efficiently into electron - positron pairs, providing a discrete feature ( a sharp edge) in the cosmic e(+) e(-) spectrum at an energy equal to the particle's mass ( typically several hundred GeV to one TeV). Although this feature is probably beyond the reach of satellite or balloon-based cosmic ray experiments ( those that distinguish the charge and mass of the primary particle), gamma-ray telescopes may provide an alternative detection method. Designed to observe very high-energy gamma rays, ACTs also observe the diffuse flux of electron-induced electromagnetic showers. The GLAST satellite, designed for gamma-ray astronomy, will also observe any high-energy showers ( several hundred GeV and above) in its calorimeter. We show that high-significance detections of an electron - positron feature from Kaluza Klein dark matter annihilations are possible with GLAST, and also with ACTs such as HESS, VERITAS or MAGIC.