$\Lambda$ and $\bar{\Lambda}$ production in central Pb-Pb collisions at 40, 80, and 158A GeV

Production of $\Lambda$ and $\bar{\Lambda}$ hyperons was measured in central Pb-Pb collisions at 40, 80, and 158A GeV beam energy on a fixed target. Transverse mass spectra and rapidity distributions are given for all three energies. The $\Lambda / \pi$ ratio at midrapidity and in full phase space shows a pronounced maximum between the highest BNL Alternating Gradient Synchrotron and 40A GeV CERN Super Proton Synchrotron energies, whereas the $\Lambda / \pi$ ratio exhibits a monotonic increase. (36 refs).