# Quark Matter 2012

12-18 August 2012
US/Eastern timezone

## Neutral meson flow in Pb-Pb collisions at the LHC with the ALICE EMCal

16 Aug 2012, 16:00
2h

Poster Global and collective dynamics

### Speaker

Fengchu Zhou (Central China Normal University (CN))

### Description

A central goal of the heavy-ion program at LHC is to study the properties of the quark-gluon plasma (QGP). The azimuthal anisotropy of particle production is a sensitive tool to study the features of the QGP. The anisotropy is typically characterized by $v_2$, the second harmonic coefficient of the Fourier series expansion of the particle azimuthal distribution with respect to the reaction plane. The observed $v_2$ is believed to be sensitive to different particle production mechanisms. At low transverse momentum ($p_{\rm t}$) $v_2$ encodes the information of the expansion driven by the initial pressure gradients. At high $p_{\rm t}$ it may be caused by path-length dependent parton energy loss. At intermediate $p_{\rm t}$ it may be related to the mechanism of quark coalescence. In this poster, we present the $v_2$ measurements of $\pi^{0}$ and $\eta$ mesons using data from the 2011 heavy-ion run at the LHC. The neutral mesons are reconstructed using the ALICE Electromagnetic Calorimeter (EMCal), while the event plane is determined by the V0 detector. The measured $v_{2}$ is reported as a function of the transverse momentum for different centrality selections. In order to study the systematic uncertainty, the $v_2$ coefficient has been extracted using both the $dN/d#varphi$ method and invariant mass method. The determination of the event plane using different subdetectors in ALICE, as well as their resolution, are also explored and discussed.

### Primary author

Collaboration ALICE (CERN, Geneva, Switzerland)

### Co-author

Fengchu Zhou (Central China Normal University (CN))

### Presentation Materials

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