Parity of theKMeson and theΛBeta-Decay Branching Ratio

The related problems of $\Lambda$ beta decay and $K_{\mu 2}$ decay (via a $\Lambda$-antiproton loop) are studied. Dispersion techniques are used to calculate the vector (axial vector) Fermi interaction coupling constant from the known $K_{\mu 2}$ lifetime and reasonable values of the strong coupling constant for the scalar (pseudoscalar) $K$ case. Each weak coupling constant is then used to place a lower limit on the $\Lambda$ beta-decay branching ratio with the result that the limit with a pseudoscalar $K$ is more than one order of magnitude smaller than that with a scalar $K$ meson. The present meager experimental information is essentially consistent with either $K$ parity, for the observed branching ratio is approximately equal to the lower limit predicted for the scalar $K$ case.