Rapidity dependent strangeness measurements in BRAHMS experiment at RHIC

Particle production of charged kaons in central Au+Au collisions at rootS(NN)=200 GeV has been studied as a function of rapidity by the BRAHMS collaboration at RHIC. The kaon spectral shapes are described well by an exponential in transverse mass for the rapidity range of 0 less than or equal to y(K) less than or equal to 3.3 with smoothly decreasing inverse slopes as the rapidity increases. For the charged kaon to pion ratios, while there is no significant rapidity dependence for the K+/pi(+) ratio, the K-/pi(-) ratio shows a significant decrease from y approximate to 1 towards higher rapidities. The systematics of K-/K+ and (p) over bar /p ratios in the measured rapidity range demonstrates a strongly correlated behaviour which can be described by thermal-statistical models.