Measurement of the Azimuthal Anisotropy of Neutral Pions in Pb-Pb Collisions at √s(NN)=2.76 TeV

Abstract

First measurements of the azimuthal anisotropy of neutral pions produced in Pb-Pb collisions at a center-of-mass energy of √s(NN)=2.76 TeV are presented. The amplitudes of the second Fourier component (v(2)) of the π(0) azimuthal distributions are extracted using an event-plane technique. The values of v(2) are studied as a function of the neutral pion transverse momentum (p(T)) for different classes of collision centrality in the kinematic range 1.6<p(T)<8.0 GeV/c, within the pseudorapidity interval |η|<0.8. The CMS measurements of v(2)(p(T)) are similar to previously reported π0 azimuthal anisotropy results from √sNN=200 GeV Au-Au collisions at RHIC, despite a factor of ∼14 increase in the center-of-mass energy. In the momentum range 2.5<pT<5.0 GeV/c, the neutral pion anisotropies are found to be smaller than those observed by CMS for inclusive charged particles.