We have studied the polarization of Ξ− and Ω− hyperons produced by high energy neutral particle beams. An unpolarized neutral beam striking a target at ±1.8 mrad produced 1.4×107Ξ−'s with an average momentum of 395 GeV/c which were unpolarized, within a sensitivity limit of 0.007, and 2.2 × 105 Ω−'s with a polarization of +0.042±0.007 at an average momentum of 374 GeV/c. A polarized neutral beam striking a target at 0.0 mrad produced 7.1×105Ξ−'s which had a polarization of -0.118±0.004 at an average momentum of 393 GeV/c and 1.8 × 104 Ω−'s with a polarization of -0.069±0.023 at an average momentum of 394 GeV/c. The polarized neutral beam measurement is in good agreement with a previous measurement. The unpolarized neutral beam results are not understood in the context of the current models of hyperon polarization.
The polarization PΞ− of Ξ− hyperons produced by 800-GeV protons has been measured for xF from 0.3 to 0.7 and pT from 0.5 to 1.5 GeV/c. PΞ− has a pT dependence similar to that of the Λ but has a different xF behavior. Also, an energy dependence of PΞ− has been observed.
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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