We present results on the measurement of $\Lambda$ and $\overline{\Lambda }$ production in $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions at $\sqrt{s_{NN}}=130\mathrm{G}\mathrm{e}\mathrm{V}$ with the PHENIX detector at the Relativistic Heavy Ion Collider. The transverse momentum spectra were measured for minimum bias and for the 5% most central events. The $\overline{\Lambda }/\Lambda$ ratios are constant as a function of $p_T$ and the number of participants. The measured net $\Lambda$ density is significantly larger than predicted by models based on hadronic strings (e.g., HIJING) but in approximate agreement with models which include the gluon-junction mechanism.

• Received 17 April 2002

DOI:https://doi.org/10.1103/PhysRevLett.89.092302