Polarization of Λ’s Produced in S + Pb Collisions at 200GeV/c per Nucleon

The Λ⁰ polarization is analyzed with the experimental data in S + Pb collisions at energy 200 GeV per nucleon, which were produced at SPS of CERN The small polarization value and the correlation between the transverse polarization and transverse momentum were obtained in Feynman parameter x_F > 0, x_F < 0 and all x_F. The results show that the non-polarization of lambda appears in the region of larger transverse momenta, say, at 1 - 2 GeV/c in P_T. The origins of polarization reduction are discussed.