Measurements 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|2π/3) over the transverse momentum range 0.4<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.

Aad, G., Abbott, B., Abdallah, J., Abdel Khalek, S., Abdinov, O., Aben, R., et al. (2014). Measurement of the long-range pseudorapidity correlations and azimuthal harmonics in √sNN = 5.02 TeV proton-lead collisions with the ATLAS detector. PHYSICAL REVIEW. C, NUCLEAR PHYSICS, 90(4), 1-29 [10.1103/PhysRevC.90.044906].

Measurement of the long-range pseudorapidity correlations and azimuthal harmonics in √sNN = 5.02 TeV proton-lead collisions with the ATLAS detector

V. Bortolotto;F. Ceradini;B. Di Micco;R. Di Nardo;D. Orestano;F. Petrucci;D. Puddu;G. Salamanna;C. Taccini;M. Trovatelli;
2014-01-01

Abstract

Measurements 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|2π/3) over the transverse momentum range 0.4<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.
2014
Aad, G., Abbott, B., Abdallah, J., Abdel Khalek, S., Abdinov, O., Aben, R., et al. (2014). Measurement of the long-range pseudorapidity correlations and azimuthal harmonics in √sNN = 5.02 TeV proton-lead collisions with the ATLAS detector. PHYSICAL REVIEW. C, NUCLEAR PHYSICS, 90(4), 1-29 [10.1103/PhysRevC.90.044906].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/119623
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