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

TL;DR

This paper reports on the spectra and rapidity densities of pions and kaons in central Au+Au collisions at 62.4 GeV, revealing universal behaviors linked to baryo-chemical potential across rapidities.

Contribution

It provides detailed measurements of meson production over a wide rapidity range and links the observed particle ratios to baryo-chemical potential, offering insights into particle production mechanisms.

Findings

Near unity $ar{ ext{p}}$/p ratio at mid-rapidity

Steep decrease of $K^-/K^+$ and $ar{ ext{p}}$/p ratios at forward rapidities

Universal behavior of kaon production related to baryo-chemical potential

Abstract

Invariant pT spectra and rapidity densities covering a large rapidity range(-0.1 < y < 3.5) are presented for $\pi^{\pm}$ 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 ($\pi^-/\pi^+ \sim 1$, $K^-/K^+ \sim 0.85$) while the anti-proton to proton ratio is $\bar{p}/p \sim 0.49$. The rapidity dependence of the $\pi^-/\pi^+$ 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.