Measurements of inclusive Δ̄° production with large χ_F at the Spp̄S collider

We report results of inclusive measurements of Δ̄° s, produced in the forward direction at the Spp̄S with √s = 630 GeV, using the UA8 small angle Roman Pot spectrometers. These measurements cover the range in Feynman-χ_F and transverse momentum, 0,6 <χ_F <1.0 and 0.4 <p₁ <0.7 GeV, respectively. Within a systematic uncertainty of ±20% on the absolute cross section measurements, the results are indistinguishable from those made by some of us in two earlier experiments at the CERN Intersecting Storage Rings, with energies, √s = 53 and 62 GeV. In the χ_F-range, 0.6-0.9, the absolute cross sections are lower by a factor of 2 to 3 than the predictions of the Lund model as embodied in the PYTHIA 5.6 and JETSET 7.3 Monte Carlo programs, indicating inadequacies in knowledge of the baryon fragmentation function. For the largest χ_F-range, 0.9-1.0, the measurements agree with the Monte Carlo predictions. We have measured the average Δ̄° polarization for our events and find (6 ± 12%), consistent with previous measurements at the ISR in the present region of χ_F-p₁,.