Phenomenology of Non-Commutative Field Theories
  We study the effects of non-commutative QED (NCQED) in fermion pair production, gamma + gamma to f + \bar{f} and Compton scattering, e + gamma to e + gamma. Non-commutative geometries 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 gamma gamma and e gamma modes. Non-commutative 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. The Compton process is sensitive to Lambda_{NC} values roughly twice as large as those accessible to the pair production process. 
Stephen Godfrey (Carleton U & DESY) and M.A. Doncheski (Penn State   University, Mont Alto)