Addressing the physics of the ridge by 2- and 3-particle correlations at STAR

Abstract

We present new results on 2-particle azimuthal ($\Delta \varphi$) correlation relative to event plane and 3-particle pseudorapidity ($\Delta \eta$) correlation at mid-rapidity in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV, measured by the STAR experiment. While jet-like correlation is symmetric, ridge is found to be asymmetric when trigger particle azimuth is between in- and out-of-plane. The charge ordering properties between associated and trigger particles are exploited to separate jet-like and ridge contributions in 3-particle $\Delta \eta$-$\Delta \eta$ correlations. We found that like-sign triplets are dominated by ridge. The separated ridge, while narrow in $\Delta \varphi$, is extremely broad in $\Delta \eta$. The ridge particles are not only uncorrelated to the trigger particle in $\Delta \eta$, but also uncorrelated between themselves.

4 pages, 4 Figures, Quark Matter 2009

References in corpus (7)

• Intra-jet correlations of high-$p_t$ hadrons from STAR
• On the Origin of the "Ridge" phenomenon induced by Jets in Heavy Ion Collisions
• Longitudinal Broadening of Quenched Jets in Turbulent Color Fields
• Reaction Plane Dependent Away-side Modification and Near-side Ridge in Au+Au Collisions
• Dependence of Ridge Formation on Trigger Azimuth: Correlated Emission Model
• Identifying the underlying physics of the ridge via 3-particle $\Delta \eta -\Delta \eta$ correlations
• Anisotropic flow background to jet-correlation relative to reaction plane: A revisit of the mathematical framework

Cited by in corpus (5)

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• Jet Medium interactions at Quark Matter 09
• Geometrical Effect on Conical Emission of Correlated Hadrons