Possible anomalous ZZγ and Zγγ couplings and Z boson spin orientation in e+e−→Zγ: The role of transverse polarization

A formalism of a general spin-1 density matrix has been used to study the effect of the CP-conserving anomalous ZZγ and Zγγ couplings on the Z boson spin orientation in e+e−→Zγ with transversely polarized beams. Analytical expressions for the transverse polarization contributions from the Standard Model and from the interference of the Standard Model and anomalous couplings amplitudes to the Z boson polarization vector and the alignment tensor have been found. The main properties of these expressions have been presented and analyzed. It has been shown that the additional directions provided by the transverse polarization vectors of simultaneously polarized beams generate new measurables which can be used for disentangling different sets of couplings.