Measurement of the azimuthal anisotropy for charged particle production in $\sqrt{s_{NN}}=2.76$ TeV lead-lead collisions with the ATLAS detector
Phys.Rev. C86 (2012) 014907
The collaboration

Abstract (data abstract)
Differential measurements of charged particle azimuthal anisotropy are presented for lead-lead collisions at a centre-of-mass energy of 2.76 TeV/nucleon. The anisotropy is characterized via a Fourier expansion of the distribution of charged particles in azimuthal angle relative to the reaction plane, with the coefficients V_n denoting the magnitude of the anisotropy. A Fourier analysis of the charged particle pair distribution in relative angle is performed extracting the coefficients V_nn.