Lambda Hyperon and Anti-Lambda Hyperon Production in Proton-Antiproton Collisions at SQRT.S = 1.8 Tev

The characteristics of Lambda and |Lambda production have been studied from data obtained from p p collisions at sqrt{rm s} = 1.8 TeV during the first running period of experiment E735 from January to May of 1987. The experiment was conducted at the Fermi National Laboratory Tevatron collider. Five million triggers from an integrated luminosity of about 1over 3 nb^{ -1} were written to tape during this initial run of E735. Using a magnetic spectrometer arm a sample of 413 Lambda's + = Lambda's were found in these events. The transverse momentum spectrum, the ratio Lambda/(all charged particles) and the ratio Lambda/proton were studied from this sample. These were compared to the findings at lower energies and also to the results of a Monte Carlo program from another experiment. The average transverse momentum was found to be 0.77 +/- 0.06 +/- 0.08, an increase of about 24% from the value found at sqrt{rm s} = 540 GeV (CERN SPS) and an increase of about 55% from sqrt{rm s} = 53 GeV (CERN ISR). The Lambda/(all charged particle) ratio was also found to increase from 0.009 +/- 0.001 at sqrt{rm s} = 53 GeV (CERN ISR) and 0.019 +/- 0.004 at sqrt{rm s} = 540 GeV (CERN SPS), to 0.026 +/- 0.002 +/- 0.004 at our energy of sqrt{rm s} = 1.8 TeV. The lambda/proton ratio was found to be 0.38 +/- 0.03 +/- 0.06. This ratio shows no increase from lower energies. The lambda/proton ratio was used to find the strangeness suppression factor (lambda) from the quark combinatoric model of hadron production. We obtain a value lambda = 0.34 +/- 0.05 in agreement with the values found at lower energies. The increase in the ratio lambda/all charged particles as a function of center of mass energy is not inconsistent with the formation of quark-gluon plasma. However, the constant ratio of lambda/proton production is not expected in quark-gluon plasma production. Moreover, our data seem to agree with the UA5 Monte Carlo data, which does not include quark-gluon plasma production. Based on Lambda production at sqrt{ rm s} = 1.8 TeV, there is no compelling evidence of quark-gluon plasma production.