Signals for noncommutative QED in eγ and γγ collisions -: art. no. 015005

We study the effects of noncommutative QED (NCQED) in fermion pair production, gamma + gamma -->f + (f) over bar, and Compton scattering, e + gamma --> e + gamma. Non-commutative geometries appear naturally in the context of suing or M theory and give rise to 3- and 4-point photon vertices and to momentum dependent phase factors in QED vertices which will have observable effects in high energy collisions. We consider e(+) e(-) colliders with energies appropriate to the TeV linear collider proposals and the multi-TeV CLIC project operating in gammagamma and egamma modes. Noncommutative scales roughly equal to the center of mass energy of the e(+)e(-) collider can be probed, with the exact value depending on the model parameters and experimental factors. However, we find that the Compton process is sensitive to Lambda(NC) values roughly twice as large as those accessible to the pair production process.