Spin polarization and alignment of the single Z boson from e+e− annihilation O

We apply a formalism of the general relativistic spin-1 density matrix (obtained by boosting the nonrelativistic one) to calculate analytically the spin orientation (polarization vector and alignment tensor) of the Z boson in the processes e+e−→ZH , e+e−→Zγ with arbitrarily polarized initial beams. Due to generality of the used technique the calculated expressions for Z boson polarization and alignment contain, in general manner, all possible spin orientation terms. Using these expressions we consider the energy–angular spectra of the final leptons in the chains of the processes e+e−→ZH,Zγ ; Z→l+l− .