MEASUREMENTS OF INCLUSIVE (LAMBDA)OVER-BAR-DEGREES PRODUCTION WITH LARGE X(F) AT THE SP(P)OVER-BARS COLLIDER

We report results of inclusive measurements of <(Lambda)over bar>degre es, produced in the forward direction at the Sp (p) over bar S with ro ot s= 630 GeV, using the UA8 small angle Roman Pot spectrometers. Thes e measurements cover the range in Feynman-x(F) and transverse momentum , 0.6 < x(F) < 1.0 and 0.4 < p(t) < 0.7 GeV, respectively. Within a sy stematic uncertainty of +/-20% on the absolute cross section measureme nts, the results are indistinguishable from those made by some of us i n two earlier experiments at the CERN Intersecting Storage Rings, with energies, root s = 53 and 62 GeV. In the x(F)-range, 0.6-0.9, the abs olute cross sections are lower by a factor of 2 to 3 than the predicti ons of the Lund model as embodied in the PYTHIA 5.6 and JETSET 7.3 Mon te Carlo programs, indicating inadequacies in knowledge of the baryon fragmentation function, For the largest x(F)-range, 0.9-1.0, the measu rements agree with the Monte Carlo predictions. We have measured the a verage <(Lambda)over bar>degrees polarization for our events and find (6+/-12%), consistent with previous measurements at the ISR in the pre sent region of x(F)-p(t). (C) 1998 Elsevier Science B.V.