Measurements of inclusive anti-Lambda0 production with large x(F) at the Spp(bar)S collider.

The UA8 collaboration Brandt, A. ; Erhan, S. ; Kuzucu, A. ; et al.
Nucl.Phys.B 519 (1998) 3-18, 1998.
Inspire Record 452309 DOI 10.17182/hepdata.32680

We report results of inclusive measurements of anti-Lambda, produced in the forward direction at the SPS with sqrt(s) = 630 GeV, using the UA8 small angle Roman Pot spectrometers. These 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 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, sqrt(s) = 53 and 62 GeV. In the x_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 x_f-range, 0.9-1.0, the measurements agree with the Monte Carlo predictions. We have measured the average anti-Lambda polarization for our events and find (6 +- 12%), consistent with previous measurements at the ISR in the present region of x_f - p_t.

3 data tables

Invariant cross section for inclusive LAMBDABAR production, multiplied by a factor 2, from the UP spectrometer.

Invariant cross section for inclusive LAMBDABAR production, multiplied by a factor 2, from the DOWN spectrometer.

The measured LAMBDABAR polarization.