Single W Boson Production in High Energy eγ Collisions

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We studied single W boson production in high energy eγ collisions and the sensitivity of various observables to the WWγ gauge boson coupling. We evaluated the helicity amplitudes including the W decay to final state fermions and all Feynman diagrams which give the same final state. At high energy, the non-resonant diagrams give significant contributions to the cross sections and should not be neglected. We first considered a √s=120 GeV e+e- collider converted to an eγ collider by backscattering a low energy laser off of one of the original electron beams. Such a collider could measure κγ to ≃± 0.09 at 95% C.L. which is the same level of precision as could be achieved at LEP200 using W pair production. We next considered single W production at a 200 GeV e+e- collider in the Weizacker-Williams approximation which can measure the WWγ vertex independently of the WWZ vertex. This process can measure κγ to ± 0.15 at 95% C.L. which is comparable to the W pair production process. Finally, we examined W production at 500 GeV and 1 TeV e+e- colliders, comparing results for photon spectra obtained from a backscattered laser and from beamstrahlung radiation. Here we found that the couplings could best be measured using the backscattered laser photons with |δκγ|≤ 0.07 and