Measurement ofΣ−Production Polarization and Magnetic Moment

We have measured the production polarization of 265- and 310-GeV/c ${\Sigma }^{-}$ in the inclusive reaction $p+\mathrm{Cu}\to {\Sigma }^{-}+X$ using 400-GeV/c protons. The polarization was analyzed via the asymmetry in the weak decay ${\Sigma }^{-}\to n+{\pi }^{-}$, and has typical values of +0.20 with respect to the direction of the cross product of the incident-proton and ${\Sigma }^{-}$ momenta. Using the spin-precession technique, we have determined the ${\Sigma }^{-}$ magnetic moment to be -1.23±0.03±0.03 nuclear magnetons, where the statistical and systematic errors are shown separately.