Polarization of Ξ- and Ω- hyperons produced from neutral beams

We have studied the polarization of {Xi}{sup {minus}} and {Omega}{sup {minus}} hyperons produced by high energy neutral particle beams. An unpolarized neutral beam striking a target at {plus_minus}1.8 mrad produced 1.4 {times}10{sup 7}{Xi}{sup {minus}}{close_quote}s with an average momentum of 395 GeV/{ital c} which were unpolarized, within a sensitivity limit of 0.007, and 2.2 {times}10{sup 5} {Omega}{sup {minus}}{close_quote}s with a polarization of +0.042{plus_minus}0.007 at an average momentum of 374 GeV/{ital c}. A polarized neutral beam striking a target at 0.0 mrad produced 7.1 {times}10{sup 5}{Xi}{sup {minus}}{close_quote}s which had a polarization of {minus}0.118{plus_minus}0.004 at an average momentum of 393 GeV/{ital c} and 1.8 {times}10{sup 4} {Omega}{sup {minus}}{close_quote}s with a polarization of {minus}0.069{plus_minus}0.023 at an average momentum of 394 GeV/{ital 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. {copyright} {ital 1996 The American Physical Society.}