Mid-rapidity $\Lambda$ and $\bar{\Lambda }$ Production in Au+Au Collisions at $\sqrt{s_{{}_{NN}}}=130$ GeV

Abstract

We report the first measurement of strange ($\Lambda$) and anti-strange ($\bar{\Lambda }$) baryon production from $\sqrt{s_{{}_{NN}}}=130$ GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Rapidity density and transverse mass distributions at mid-rapidity are presented as a function of centrality. The yield of $\Lambda$ and $\bar{\Lambda }$ hyperons is found to be approximately proportional to the number of negative hadrons. The production of $\bar{\Lambda }$ hyperons relative to negative hadrons increases very rapidly with transverse momentum. The magnitude of the increase cannot be described by existing hadronic string fragmentation models.

6 pages, 4 figures