Signals for Non-Commutative Interactions at Linear Colliders

Recent theoretical results have demonstrated that non-commutative geometries naturally appear within the context of string/M-theory. One consequence of this possibility is that QED takes on a non-abelian nature due to the introduction of 3- and 4-point functions. In addition, each QED vertex acquires a momentum dependent phase factor. We parameterize the effects of non-commutative space-time co-ordinates and show that they lead to observable signatures in several $2\to 2$ QED processes in $e^+e^-$ collisions. In particular, we examine pair annihilation, Moller and Bhabha scattering, as well as $\gamma\gamma\to\gamma\gamma$ scattering and show that non-commutative scales of order a TeV can be probed at high energy linear colliders.