In the Brookhaven National Laboratory 20.8-GeV/c negative-hyperon beam, we have measured the production ratios $\frac{{\Sigma }^{-}}{{\pi }^{-}}$, $\frac{{\Xi }^{-}}{{\pi }^{-}}$, and $\frac{{\Sigma }^{-}}{{\Xi }^{-}}$ by 29.4-GeV/c protons incident on Al and ${\mathrm{Al}}_2$${\mathrm{O}}_3$ targets. We have also measured the asymmetry parameter in the decay ${\Xi }^{-}\to \Lambda {\pi }^{-}$ and find ${\alpha }_{{\Xi }^{-}}=-0.49\mathrm{}\pm 0.04$.

• Received 10 July 1979

DOI:https://doi.org/10.1103/PhysRevD.21.12