The polarization of protons from the decay of polarized ${\Sigma }^{+}$ hyperons has been measured by scattering the protons in a carbon-plate spark chamber. A sample of 1335 useful scatters gave ${\alpha }_0=-0.98\mathrm{}\pm 0.05$ and ${\varphi }_0=22\mathrm{}°\pm 90°$, where $tan{\varphi }_0=\frac{{\beta }_0}{{\gamma }_0}$. Using the data on ${\Sigma }^{+}\to n{\pi }^{+}$ and ${\Sigma }^{-}\to n{\pi }^{-}$ and fitting to the $\left|\Delta \overrightarrow{\mathrm{I}}\right|=\frac{1}{2}$ rule gave ${\chi }^2=0.3\mathrm{}$ for 2 degrees of freedom.

• Received 10 November 1969

DOI:https://doi.org/10.1103/PhysRevLett.24.165