Isotopic Spin Selection Rule|ΔI|=12for the Decays of Strange Particles

Abstract

Decay processes of strange particles are re-examined under the assumption of the selection rule $\left|\Delta I\right|=\frac{1}{2}$, when all particles concerned have isotopic spins, but parity is not necessarily conserved. Some of the results obtained before still hold as they are, even if parity nonconservation is taken into consideration. However, the relation between the branching ratio $\frac{({\Sigma }^{+}\to p+{\pi }^0)}{({\Sigma }^{+}\to n+{\pi }^{+})}$ and the ratio of lifetimes $\frac{\tau \left({\Sigma }^{-}\right)}{\tau \left({\Sigma }^{+}\right)}$ is changed by parity nonconservation. The experimental results on $\Sigma$ particles may be interpreted as indicating comparable magnitudes for parity-conserving and parity-nonconserving terms. Some results based on $\left|\Delta I\right|=\frac{1}{2} \mathrm{and} \frac{3}{2}$ are also discussed for these particles.