Measurement of elliptic and higher order flow from ATLAS experiment at the LHC

Abstract

We present a differential measurement of the azimuthal anisotropy of charged hadron production in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}$=2.76 TeV. This azimuthal anisotropy is expanded into a Fourier series in azimuthal angle, where the coefficient for each term, $v_n$, characterizes the magnitude of the anisotropy at a particular angular scale. We extract $v_2-v_6$ via a discrete Fourier analysis of the two-particle $\Delta \varphi -\Delta \eta$ correlation with a large $\Delta \eta$ gap ($|\Delta \eta |>2$), and via an event plane method based on the Forward Calorimeter. Significant $v_2-v_6$ values are observed over a broad range in $\pT$, $\eta$ and centrality, and they are found to be consistent between the two methods in the transverse momentum region $\pT<3-4$ GeV. This suggests that the measured $v_2-v_6$ obtained from two-particle correlations at low $\pT$ with a large $\Delta \eta$ gap are consistent with the collective response of the system to the initial state geometry fluctuations, and is not the result of jet fragmentation or resonance decay.

Proceedings of plenary talk at the XXII International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, Quark Matter 2011, Annecy

References in corpus (6)

• Dihadron azimuthal correlations in Au+Au collisions at sqrt(s_NN)=200 GeV
• Anisotropic flow in sqrt(s)=2.76 TeV Pb+Pb collisions at the LHC
• Translation of collision geometry fluctuations into momentum anisotropies in relativistic heavy-ion collisions
• System-size independence of directed flow at the Relativistic Heavy-Ion Collider
• Quenching and Tomography from RHIC to LHC
• The second act of hydro: small perturbations

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• Anisotropic flow in event-by-event ideal hydrodynamic simulations of sqrt(s_{NN})=200 GeV Au+Au collisions
• Theoretical and Experimental Constraints for the Equation of State of Dense and Hot Matter
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• Quenching and Tomography from RHIC to LHC
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• Initial state anisotropies and their uncertainties in ultrarelativistic heavy-ion collisions from the Monte Carlo Glauber model
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• Event-by-event azimuthal anisotropy of jet quenching in relativistic heavy ion collisions
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