$\Lambda$ and $\bar{\Lambda }$ Production in Central Pb-Pb Collisions at 40, 80, and 158 A$\cdot$GeV

Abstract

Production of Lambda and Antilambda hyperons was measured in central Pb-Pb collisions at 40, 80, and 158 A$\cdot$GeV beam energy on a fixed target. Transverse mass spectra and rapidity distributions are given for all three energies. The $\Lambda /\pi$ ratio at mid-rapidity and in full phase space shows a pronounced maximum between the highest AGS and 40 A$\cdot$GeV SPS energies, whereas the $\bar{\Lambda }/\pi$ ratio exhibits a monotonic increase.

5 pages, 7 figures, 1 table, submitted to Phys. Rev. Lett