  Regularized quantum information metrics are calculated for the scattering
process $e^-e^+ \rightarrow \gamma,Z\rightarrow \mu^-\mu^+$ that has a witness
photon entangled with the initial electron-positron state. Unitarity implies
the correct regularization of divergences that appear in both the final density
matrix and von Neumann entanglement entropies. The entropies are found to
quantify uncertainty or randomness. The variation of information, entanglement
entropy, and correlation between the muon's and witness photon's helicities are
found to convey equivalent information. The magnitude of the muon's expected
helicity rises (falls) as the helicity entropy falls (rises). Area, or the
scattering cross section, is a source of entropy for the muon's helicity
entropy and momentum entropy. The muon's differential angular entropy
distribution is similar to the differential angular cross section distribution,
capturing the forward-backward asymmetry at high center of mass energies.
