  Traditional analysis of $g=2(1+\kappa )$ experiments for charged leptons use
a classical spin vector picture. For muons, we here employ a more exact Dirac
quantum four component spinor theory. Survival probabilities (including wave
packet effects) are computed. These oscillate with the frequency $\Omega
=(\kappa eB/Mc)$ as has been assumed in previous muon $(g-2)$ experimental
analyses; i.e. muon survival probability oscillations are already at the root
of previous succesful $(g-2)$ measurements. Further oscillations should also be
observed if mixed neutrino mass matrices were to enter into the reactions (e.g.
$\pi^+ \to \mu^+ +\nu_\mu$) producing muons.
