Kμ3Decay: Tests for Time Reversal and the Two-Component Theory

Abstract

The $K_{\mu 3}$ decay is investigated with special attention to possible muon polarization normal to the decay plane [${\sigma }_{\mu }·({\mathrm{p}}_{\pi }\times {\mathrm{p}}_{\mu })$] which can be detected by observing an "up-down" asymmetry in the electron distribution in the subsequent parity-nonconserving muon decay. If the $K$ particle is spinless or is unpolarized, the presence of such polarization would indicate that invariance under time reversal is violated in the $K_{\mu 3}$ decay. This polarization is calculated field-theoretically for the spinless $K$ particle. In addition a sensitive test for the two-component theory of the neutrino is proposed for the decay configuration in which the three decay products are collinear.