The ratio of the cross section for 2' inclusive production to the cross section for A0 inclusive production has been measured with 28.5-GeV/c protons incident on a beryllium target at an average laboratory production angle of 4". This ratio was measured to be 0.278?0.011-C0.05, where the uncertainties are statistical and systematic in that order. The ratio does not depend strongly on the momentum of the produced particle between 10 and 24 GeV/c. The effect of Z0 contamination on previous determinations of the polarization of inclusively produced Ao's is discussed.

The polarization of yo hyperons produced in an inclusive reaction has been measured for the first time. From a sample of I l 000 events produced by 28.5 GeV/c protons in the reaction p + Be-,Z ° + X, the 3-o polarization has a value of + 0.28 _+ 0.13 at pt= 1.01 GeV/c and Xr=0.60. The polarization of 53000 A hyperons produced from 28.5 GeV/c protons in the reaction p + Be-,A + X has also been measured in the kinematic range 0.64

The ratio of the cross section for Z ° inclusive production to the cross section for A ° inclusive production has been measured with 28.5 GeV/c protons incident on a beryllium target at an average laboratory production angle of 4 °. This ratio was measured to be 0.278-+ 0.011 +-0.05 where the uncertainties are statistical and systematic in that order. The ratio does not depend strongly on the momentum of the produced particle between 10 and 24 GeV/c. The effect of Z0 contamination on previous determinations of the polarization of inclusively produced A ° 's is discussed. Measurements of the inclusive production of A 0 hyperons by protons [1-4] on various targets have not distinguished between A°'s produced directly and A°'s arising from the decay Z 0 ~ A 0 + 3'. Comparisons with theoretical models .1 [6] of A 0 polarization in inclusive production by protons are compromised somewhat due to the y0 contribution to the A ° sample. In K-p interactions, the Z 0 contribution was found [7] to be substantial-almost 30% at 8.25 GeV/c. In this paper, the first measurement with incident protons of the ratio of the cross section for Z 0 inclusive production to the cross section for A 0 inclusive production is reported. The effect on previous determinations of A 0 polarization is presented.