Angular correlations between unidentified charged trigger (t) and associated (a) particles are measured by the ALICE experiment in Pb–Pb collisions at √sNN = 2.76 TeV for transverse momenta
0.25 < p(taT) < 15 GeV/c, where p (tT) > p(aT) . The shapes of the pair correlation distributions are studied in a variety of collision centrality classes between 0 and 50% of the total hadronic cross section for particles in the pseudorapidity interval |η| < 1.0. Distributions in relative azimuth φ ≡ φt − φa are analyzed for |η| ≡ |ηt − ηa| > 0.8, and are referred to as “long-range correlations”. Fourier components Vn ≡ cos(nφ) are extracted from the long-range azimuthal correlation functions. If particle
pairs are correlated to one another through their individual correlation to a common symmetry plane, then the pair anisotropy Vn(p(tT) , p(aT) ) is fully described in terms of single-particle anisotropies vn(pT) as Vn(p(tT), p(aT)) = vn(p(tT)vn(paT). This expectation is tested for 1 ≤ n ≤ 5 by applying a global fit of all
Vn(p(tT), p(aT) to obtain the best values vn{GF}(pT ). It is found that for 2 ≤ n ≤ 5, the fit agrees well with data up to p(aT) ~ 3–4 GeV/c, with a trend of increasing deviation as p(tT) and p(aT) are increased or as collisions become more peripheral. This suggests that no pair correlation harmonic can be described over the full 0.25 < pT < 15 GeV/c range using a single vn(pT) curve; such a description is however approximately possible for 2 ≤ n ≤ 5 when p(aT) <4 GeV/c. For the n = 1 harmonic, however, a single v1(pT)
curve is not obtained even within the reduced range p(aT) <4 GeV/c.
