Self-Consistent Model for Nonleptonic Decays of $\Sigma$ and $\Lambda$ Hyperons

A self-consistent calculation of pionic $\Sigma$ and $\Lambda$ decays has been carried out in the pole approximation of an $S$ matrix approach in order to get information on (a) the angular momentum in which the decay ${\Sigma }^{+}\to n{\pi }^{+}$ takes place, (b) the relative ($\Sigma \Lambda$) parity, (c) the possible existence of other than global symmetric solutions. On the basis of existing experimental data, the model predicts that ${\Sigma }^{+}\to n{\pi }^{+}$ decay must occur in the $s$ wave, and, somewhat less definitely, that ($\Sigma \Lambda$) parity is even.