# Directed Flow of Identified Particles in Au + Au Collisions at $\sqrtsNN = 200$ GeV at RHIC

Abstract : STAR's measurements of directed flow ($v_1$) around midrapidity for $\pi^{\pm}$, K$^{\pm}$, K$_S^0$, $p$ and $\bar{p}$ in Au + Au collisions at $\sqrtsNN = 200$ GeV are presented. A negative $v_1(y)$ slope is observed for most of produced particles ($\pi^{\pm}$, K$^{\pm}$, K$_{S}^{0}$ and $\bar{p}$). The proton $v_1(y)$ slope is found to be much closer to zero compared to antiprotons. A sizable difference is seen between $v_1$ of protons and antiprotons in 5-30% central collisions. The $v_1$ excitation function is presented. Comparisons to model calculations (RQMD, UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. Anti-flow alone cannot explain the centrality dependence of the difference between the $v_1(y)$ slopes of protons and antiprotons.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00653198
Contributor : Sylvie Flores <>
Submitted on : Monday, December 19, 2011 - 9:10:56 AM
Last modification on : Thursday, February 7, 2019 - 2:58:52 PM

### Citation

M. Adamczyk, W. Borowski, S. Kabana. Directed Flow of Identified Particles in Au + Au Collisions at $\sqrtsNN = 200$ GeV at RHIC. Physical Review Letters, American Physical Society, 2011, 108, pp.202301. ⟨10.1103/PhysRevLett.108.202301⟩. ⟨in2p3-00653198⟩

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