We have measured the production polarization of 265- and 310-GeV/c Σ− in the inclusive reaction p+Cu→Σ−+X using 400-GeV/c protons. The polarization was analyzed via the asymmetry in the weak decay Σ−→n+π−, and has typical values of +0.20 with respect to the direction of the cross product of the incident-proton and Σ− momenta. Using the spin-precession technique, we have determined the Σ− magnetic moment to be -1.23±0.03±0.03 nuclear magnetons, where the statistical and systematic errors are shown separately.
The polarization of Ξ¯ + hyperons produced by 800-GeV/c protons in the inclusive reaction p+Be→Ξ¯ ++X has been measured. The average polarization of the Ξ¯ +, at a mean xF=0.39 and pt=0.76 GeV/c, is -0.097±0.012±0.009. The magnetic moment of the Ξ¯ + is 0.657±0.028±0.020 nuclear magneton.
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