| We studied the kaon production in Au+Au collisions at = 130 GeV. We obtained a K+/ K− ratio of 1.14 ± 0.01 at mid-rapidity for central collisions. The ratio indicates that the mid-rapidity region is almost (but not completely) net-baryon free. This K +/K− ratio value can be simply related to (or even be predicted by) other measured particle/antiparticle ratios in the framework of a simple quark-counting model. Our measurement is compatible and in good agreement with the other measurements performed in the same experiment. The observed trend in these particle ratios is similar to that observed in heavy-ion collisions at the lower CERN-SPS energies.; We also report first measurement of the transverse mass spectra and mid-rapidity yields of charged kaons in these collisions. The spectra are well described by an exponential in transverse mass, with a slope parameter of about 280 MeV for central collisions, showing slight increase with the collision centrality. For central collisions, the mid-rapidity yields are about 48 for K+, 42 for K−, and the negative kaon to pion ratio is 0.15 ± 0.01(stat) ± 0.02(sys). No strong centrality dependence is found for the kaon to pion ratios. The K/π ratios are found to be enhanced by about 50% from similar energy p+ p and p¯+p collisions. The negative kaon to pion ratio is found, as a function of the pion transverse energy density, to increase as a function of the colliding energy, and seems to saturate at the RHIC energy. |
