Partonic flow and $ϕ$-meson production in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

Abstract

We present first measurements of the $ϕ$-meson elliptic flow ($v_{2}(p_{T})$) and high statistics $p_{T}$ distributions for different centralities from $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions at RHIC. In minimum bias collisions the $v_{2}$ of the $ϕ$ meson is consistent with the trend observed for mesons. The ratio of the yields of the $Ω$ to those of the $ϕ$ as a function of transverse momentum is consistent with a model based on the recombination of thermal $s$ quarks up to $p_{T}\sim 4$ GeV/$c$, but disagrees at higher momenta. The nuclear modification factor ($R_{CP}$) of $ϕ$ follows the trend observed in the $K^{0}_{S}$ mesons rather than in $Λ$ baryons, supporting baryon-meson scaling. Since $ϕ$-mesons are made via coalescence of seemingly thermalized $s$ quarks in central Au+Au collisions, the observations imply hot and dense matter with partonic collectivity has been formed at RHIC.

6 pages, 4 figures, submit to PRL