Polarization of a vector boson produced in decay of a heavy fermion in an arbitrary frame

Understand

We consider processes where an electroweak gauge boson ($W$ and $Z$) is produced in the decays of a heavy fermion.

• The polarization state of the produced gauge boson is given in terms of a vector polarization and a rank-2 tensor polarization.
• In the rest frame of the mother fermion, these are given directly by the dynamical parameters of the underlying theory.
• In a frame where the mother particle is moving, the polarization parameters of the gauge boson are dependent additionally upon kinematical factors.