Σ−Decay Parameters

Abstract

We have measured the decay parameters of ${\Sigma }^{-}\to n+{\pi }^{-}$. We find ${\alpha }_{-}=-0.104\mathrm{}\pm 0.04$. Defining $\varphi$ by ${\beta }_{-}={(1-{{\alpha }_{-}}^2)}^{-\frac{1}{2}}sin\varphi$, ${\gamma }_{-}={(1-{{\alpha }_{-}}^2)}^{-\frac{1}{2}}cos\varphi$, we find $\varphi =-22\mathrm{}°\pm 30°$, i.e., the decay occurs mainly through the $S$-wave channel.