Probing the weak boson sector in γe→Ze

We study possible deviations from the Standard Model in the reaction γe→Ze at a 500 GeV e⁺e^- collider. As a photon source we use a laser backscattered photon beam. We investigate the most general γZγ and γZZ vertices including operators up to energy-dimension-six which are Lorentz invariant. These vertices require four extra parameters; two are CP-conserving, h₁^γ and h₁^Z, and two are CP-violating, h₂^γ and h₂^Z. We present analytical expressions of the helicity amplitudes for the process γe→Ze for arbitrary values of anomalous couplings. Assuming Standard Model values are actually measured we present the allowed region in the (h₁^γ, h₁^Z) plane at the 90% confidence level. We then show how the angular correlation of the Z decay products can be used to extract detailed information on the anomalous (especially CP-violating)γZγ and γZZ couplings.