  We consider massive Dirac electron antineutrino to be observed in the muon
decay, $\mu^{-} \rightarrow e^- +\bar{\nu}_{e} + \nu_{\mu}$, at rest in the LAB
reference frame. A computation of $\bar{\nu}_{e}$ differential direct spectral
shape and angular distribution was performed. This has resulted in transverse
component of the neutrino polarization emerging from the nonstandard S, T
sector of the Lorentz structure in the Fermi leptonic charged weak interaction.
The calculation is based on empirical values of the coupling parameters.
