Aad, G.Abbott, B.Abdallah, J.Khalek, S. AbdelAbdinov, O.Aben, R.Abi, B.Izen, Joseph M.Leyton, MichaelLou, XinchouNamasivayam, HarisankarReeves, KendallATLAS Collaboration2015-01-162015-01-162014-10-012014-10-010556-2813http://hdl.handle.net/10735.1/4270Measurements of two-particle correlation functions and the first five azimuthal harmonics, v₁ to v₅, are presented, using 28 nb⁻¹ of p + Pb collisions at a nucleon-nucleon center-of-mass energy of √sNN = 5.02 TeV measured with the ATLAS detector at the LHC. Significant long-range "ridgelike" correlations are observed for pairs with small relative azimuthal angle (|Δϕ| < π/3) back-to-back pairs (|Δϕ| > )π/3) over the transverse momentum range 0.4 < pT < 12 GeV and in different intervals of event activity. The event activity is defined by either the number of reconstructed tracks or the total transverse energy on the Pb-fragmentation side. The azimuthal structure of such long-range correlations is Fourier decomposed to obtain the harmonics vn as a function of pT and event activity. The extracted vn values for n=2 to 5 decrease with n. The v₂ and v₃ values are found to be positive in the measured pT range. The v₁ is also measured as a function of pT and is observed to change sign around pT ≈ 1.5–2.0 GeV and then increase to about 0.1 for pT > 4 GeV. The v₂(pT), v₃(pT), and v₄(pT) are compared to the vn coefficients in Pb+Pb collisions at √sNN = 2.76 TeV with similar event multiplicities. Reasonable agreement is observed after accounting for the difference in the average pT of particles produced in the two collision systems.en-USCC BY 3.0 (Attribution)©2014 CERN, for the ATLAS Collaborationhttp://creativecommons.org/licenses/by/3.0/Proton-lead interactionsLead-lead interactionsEvent activitiesFourier seriesTextAad, G., B. Abbott, J. Abdallah, S. Abdel Khalek, et al. 2014. "Measurement of long-range pseudorapidity correlations and azimuthal harmonics in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector." Physical Review C 90(4): 044906.904