RELATIVE CORRECTIONS TO ELECTRON POLARIZATION IN MUON DECAY

We calculate and discuss radiative corrections to the full polarization vector of the decay electron in muon decay, for a large class of effective four-fermion interactions, including for the first time its transverse and normal components. The corrections are found to be large at low electron energies but decreasing rapidly below the 1% level as the energy is increased. Thus, a precision measurement of the full electron polarization at energies in the upper half of the spectrum will be sensitive to deviations from the expected V - A couplings. At these energies such deviations cannot be simulated by radiative corrections. We comment on present and future experiments on muon decay. © 1979.