Kaon and Pion Production in Central Au+Au Collisions at \sqrt{s_{NN}}=62.4 GeV

Abstract

Invariant pT spectra and rapidity densities covering a large rapidity range(-0.1 < y < 3.5) are presented for $\ddot{I}{€}^{\pm }$ and $K^{\pm }$ mesons from central Au+Au collisions at $\sqrt{s_{NN}}$ = 62.4 GeV. The mid-rapidity yields of meson particles relative to their anti-particles are found to be close to unity ($\ddot{I}{€}^{-}/\ddot{I}{€}^{+}\sim 1$, $K^{-}/K^{+}\sim 0.85$) while the anti-proton to proton ratio is $\bar{p}/p\sim 0.49$. The rapidity dependence of the $\ddot{I}{€}^{-}/\ddot{I}{€}^{+}$ ratio is consistent with a small increase towards forward rapidities while the $K^{-}/K^{+}$ and $\bar{p}/p$ ratios show a steep decrease to $\sim$ 0.3 for kaons and 0.022 for protons at $y\sim 3$. It is observed that the kaon production relative to its own anti-particle as well as to pion production in wide rapidity and energy ranges shows an apparent universal behavior consistent with the baryo-chemical potential, as deduced from the $\bar{p}/p$ ratio, being the driving parameter.

Submitted to PLB, 6 journal pages, 7 figures