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

Abstract

We report the first measurement of strange ($Λ$) and anti-strange ($\barΛ$) 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 $Λ$ and $\barΛ$ hyperons is found to be approximately proportional to the number of negative hadrons. The production of $\barΛ$ 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.