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.
Categories: nucl-ex