Abstract: 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 (p T) and collision centrality over a broad range in relative pseudorapidity (??) and the full range of relative azimuthal angle (??). The observed two-dimensional correlation structure in ?? and ?? is characterised by a narrow peak at (??,??)?(0,0) from jet-like correlations and a long-range structure that persists up to at least |??|=4. An enhancement of the magnitude of the short-range jet peak is observed with increasing centrality, especially for particles of p T 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 p T?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 p T of 1?3 GeV/c, as a function of the trigger particle p T up to 20 GeV/c and over the full centrality range.

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