Strange antiparticle-to-particle ratios at mid-rapidity in sNN=130 GeV Au+Au collisions

Abstract Values of the ratios in the mid-rapidity yields of Λ / Λ =0.71±0.01( stat. )±0.04( sys. ) , Ξ + / Ξ − =0.83±0.04( stat. )±0.05( sys. ) , Ω + / Ω − =0.95±0.15( stat. )±0.05( sys. ) and K + /K − =1.092±0.023(combined) were obtained in central s NN =130 GeV Au+Au collisions using the STAR detector. The ratios indicate that a fraction of the net- baryon numberfrom the initial system is present in the excess of hyperonsover antihyperons at mid-rapidity. The trend in the progression of the baryonratios, with increasing strange quarkcontent, is similar to that observed in heavy-ion collisions at lower energies. The value of these ratios may be related to the charged kaon ratio in the framework of simple quark-counting and thermal models.