Observation of Associated Near-Side and Away-Side Long-Range Correlations in sNN=5.02TeV Proton-Lead Collisions with the ATLAS Detector
Abstract
Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in sNN=5.02TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos2Δϕ modulation for all ΣETPb ranges and particle pT.
- Publication:
-
Physical Review Letters
- Pub Date:
- May 2013
- DOI:
- 10.1103/PhysRevLett.110.182302
- arXiv:
- arXiv:1212.5198
- Bibcode:
- 2013PhRvL.110r2302A
- Keywords:
-
- 25.75.-q;
- Relativistic heavy-ion collisions;
- High Energy Physics - Experiment
- E-Print:
- 5 pages plus author list (18 pages total), 4 figures, submitted to Physical Review Letter. Additional auxiliary plots can be found at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2012-13/. Change to reference w.r.t v1. Revision corresponds to published version