A relativistic moving particle, e.g. muon $\mu^+$, described by its four-momentum vector $p_\mu$, charge $e$ and with a given spin polarization, ${\bf S}=(S_x,S_y,S_z)$, decays into three particles, e.g. $\mu^+\to\nu_\mu e^+\bar{\nu}_e$.
- How does one determine the spin polarizations of decay products? (what literature to search)
- Is the treatment different if particle decays in a (homogeneous) magnetic field or for non-relativistic velocities?
