2012/01/31 by CMS Collaboration, S. Chatrchyan, V. Khachatryan +98
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex #nucl-ex
paper · pdf · doi:10.1140/epjc/s10052-012-2012-3
published as Eur. Phys. C 72 (2012) 10052 · Submitted to the European Physical Journal C
openalex publication_date 2012/05/01 · arxiv created 2013/01/22 · arxiv updated 2013/01/23 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/04
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 (Δ η ) and the full range of relative azimuthal angle (Δ ϕ ). The observed two-dimensional correlation structure in Δ η and Δ ϕ is characterised by a narrow peak at (Δ η ,Δ ϕ )≈(0,0) from jet-like correlations and a long-range structure that persists up to at least |Δ η |=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.