Centrality dependence of dihadron correlations and azimuthal anisotropy harmonics in PbPb collisions at sqrt(s[NN]) = 2.76 TeV
(2012) European Physical Journal C. Particles and Fields — Vol. 72, p. 2012 (2012)
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- Measurements from the CMS experiment at the LHC of dihadron correlations for charged particles produced in PbPb collisions at a nucleon-nucleon centre-of-mass energy of 2.76 TeV are presented. The results are reported as a function of the particle transverse momenta (pt) and collision centrality over a broad range in relative pseudorapidity [Delta(eta)] and the full range of relative azimuthal angle [Delta(phi)]. The observed two-dimensional correlation structure in Delta(eta) and Delta(phi) is characterised by a narrow peak at Delta(eta), Delta(phi) approximately (0, 0) from jet-like correlations and a long-range structure that persists up to at least |Delta(eta)| = 4. An enhancement of the magnitude of the short-range jet peak is observed with increasing centrality, especially for particles of pt around 1-2 GeV/c. The long-range azimuthal dihadron correlations are extensively studied using a Fourier decomposition analysis. The extracted Fourier coefficients are found to factorise into a product of single-particle azimuthal anisotropies up to pt approximately 3-3.5 GeV/c for at least one particle from each pair, except for the second-order harmonics in the most central PbPb events. Various orders of the single-particle azimuthal anisotropy harmonics are extracted for associated particle pt of 1-3 GeV/c, as a function of the trigger particle pt up to 20 GeV/c and over the full centrality range.
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CMS Collaboration, Quertenmont, L., Chatrchyan, S., Basegmez, S., Bruno, G., Ceard, L., de Favereau de Jeneret, J., Delaere, C., Du Pree, T., Favart, D., Forthomme, L., Giammanco, A., Grégoire, G., Hollar, J., Lemaitre, V., Liao, J., Militaru, O., Nuttens, C., Pagano, D., et al. (2012). Centrality dependence of dihadron correlations and azimuthal anisotropy harmonics in PbPb collisions at sqrt(s[NN]) = 2.76 TeV. European Physical Journal C. Particles and Fields, 72, 2012. https://doi.org/10.1140/epjc/s10052-012-2012-3 (Original work published 2012)