Rapidity dependence of charge particle yields for Au+Au at √sNN = 200 GeV

Yields of charged particles (π±, K±, p and p-bar) have been derived from spectra measured with BRAHMS for the reaction Au+Au at √sNN = 200 GeV, as a function of rapidity in the range y = 0 to y ∼ 3 for the 10% most central events. The yields peak at mid-rapidity with a small decrease in the range vertical bar y vertical bar < or approx. 1 but they drop significantly at higher rapidities except for the protons. At y = 0, the ((K-)/(π-)) ratio is 0.18 ± 0.02 (syst), very close to the ((K+)/(π+)) ratio equal to 0.19 ± 0.02 (syst). but at y = 3, ((K-)/(π-)) drops to 0.12 ± 0.02 (syst) while ((K+)/(π+)) remains constant