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

Abstract

Values of the ratios in the mid-rapidity yields of Λ̄/Λ=0.71±0.01(stat.)±0.04(sys.), Ξ̄+/Ξ−=0.83±0.04(stat.)±0.05(sys.), Ω̄+/Ω−=0.95±0.15(stat.)±0.05(sys.) and K+/K−=1.092±0.023(combined) were obtained in central sNN=130 GeV Au+Au collisions using the STAR detector. The ratios indicate that a fraction of the net-baryon number from the initial system is present in the excess of hyperons over antihyperons at mid-rapidity. The trend in the progression of the baryon ratios, with increasing strange quark content, 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.