Indirect Signatures of CP Violation in the Processes γγ → γγ , γZ , and ZZ

Future e+e− colliders will likely have the option of operating in γγ or eγ collision modes [1]. These modes are reached by Compton scattering laser light off one or more of the incoming fermion beams, and then colliding the resulting high energy photons with the remaining fermion beam or with each other. There is a large potential for eγ and γγ collisions to elucidate possible physics beyond the Standard Model; previous investigations have focused on anomalous couplings, searches for extra dimensions, properties of supersymmetry, and a broad host of other topics [2]. In this paper we will show that γγ → γγ, γZ , and ZZ at a photon collider can provide sensitive tests of CP violation in quartic gauge boson interactions. Assuming a center of mass energy √ see = 1 TeV and an integrated luminosity Lee = 100 fb−1 for the parent e+e− collider, we will find that new physics scales of 2–3 TeV can be probed. A more complete summary of these results can be found in [3].