Limits onCP-Invariance Violation inKμ3Decays

Measurements of the polarization of ${\mu }^{+}$ from the decay of ${K_L}^0$ mesons gives a mean value of 0.0021 ± 0.0048 for the polarization in the direction (${\overrightarrow{\mathrm{p}}}_{\pi }\times {\overrightarrow{\mathrm{p}}}_{\mu }$) normal to the plane of decay. The ratio of the normal to the transverse polarization in the c.m. system is 0.0041 ± 0.0092 and the value of $\mathrm{Im}\xi$ is deduced to be 0.012 ± 0.026, not significantly different from $\mathrm{Im}\xi =0.008\mathrm{}$ expected if the decay were invariant under $\mathrm{CP}$ (or $T$).