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

G. Aad; B. Abbott; J. Abdallah; S. Abdel-Khalek; O. Abdinov; Mogens Dam; Jørn Dines Hansen; Jørgen Beck Hansen; Stefania Xella; Peter Henrik Hansen; Troels Christian Petersen; Lotte Ansgaard Thomsen; Sascha Mehlhase; Morten Dam Jørgensen; Almut Maria Pingel; Ask Emil Løvschall-Jensen; Alejandro Alonso Diaz; James William Monk; Graig Wiglesworth; Lars Egholm Pedersen; Gorm Aske Gram Krohn Galster

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

G. Aad, B. Abbott, J. Abdallah, S. Abdel-Khalek, O. Abdinov, Mogens Dam, Jørn Dines Hansen, Jørgen Beck Hansen, Stefania Xella, Peter Henrik Hansen, Troels Christian Petersen, Lotte Ansgaard Thomsen, Sascha Mehlhase, Morten Dam Jørgensen, Almut Maria Pingel, Ask Emil Løvschall-Jensen, Alejandro Alonso Diaz, James William Monk, Graig Wiglesworth, Lars Egholm PedersenGorm Aske Gram Krohn Galster

Experimental Particle Physics

115 Citations (Scopus)

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 (|Δϕ|<π/3) and back-to-back pairs (|Δφ|>2π/3) over the transverse momentum range 0.4<p_T<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 ν_n as a function of pT and event activity. The extracted ν_n values for n=2 to 5 decrease with n. The ν₂ and ν₃ values are found to be positive in the measured pT range. The ν₁ 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 ν₂ (pT), ν₃ (pT), and ν₄ (pT) are compared to the ν_n 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.

Original language	English
Article number	044906
Journal	Physical Review C (Nuclear Physics)
Volume	90
ISSN	0556-2813
Publication status	Published - 9 Oct 2014

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http://dx.doi.org/10.1103/PhysRevC.90.044906

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Aad, G., Abbott, B., Abdallah, J., Abdel-Khalek, S., Abdinov, O., Dam, M., Hansen, J. D., Hansen, J. B., Xella, S., Hansen, P. H., Petersen, T. C., Thomsen, L. A., Mehlhase, S., Jørgensen, M. D., Pingel, A. M., Løvschall-Jensen, A. E., Alonso Diaz, A., Monk, J. W., Wiglesworth, G., ... Galster, G. A. G. K. (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 (Nuclear Physics), 90, [044906]. http://dx.doi.org/10.1103/PhysRevC.90.044906

Aad, G, Abbott, B, Abdallah, J, Abdel-Khalek, S, Abdinov, O, Dam, M , Hansen, JD , Hansen, JB , Xella, S , Hansen, PH , Petersen, TC, Thomsen, LA, Mehlhase, S, Jørgensen, MD, Pingel, AM, Løvschall-Jensen, AE, Alonso Diaz, A, Monk, JW, Wiglesworth, G, Pedersen, LE & Galster, GAGK 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 (Nuclear Physics), vol. 90, 044906. < http://dx.doi.org/10.1103/PhysRevC.90.044906>

@article{9ed9841d951d46bc8fddd70b211f4712,

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

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 (|Δϕ|<π/3) and back-to-back pairs (|Δφ|>2π/3) over the transverse momentum range 0.4T<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 νn as a function of pT and event activity. The extracted νn values for n=2 to 5 decrease with n. The ν2 and ν3 values are found to be positive in the measured pT range. The ν1 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 ν2 (pT), ν3 (pT), and ν4 (pT) are compared to the νn 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.",

author = "G. Aad and B. Abbott and J. Abdallah and S. Abdel-Khalek and O. Abdinov and Mogens Dam and Hansen, {J{\o}rn Dines} and Hansen, {J{\o}rgen Beck} and Stefania Xella and Hansen, {Peter Henrik} and Petersen, {Troels Christian} and Thomsen, {Lotte Ansgaard} and Sascha Mehlhase and J{\o}rgensen, {Morten Dam} and Pingel, {Almut Maria} and L{\o}vschall-Jensen, {Ask Emil} and {Alonso Diaz}, Alejandro and Monk, {James William} and Graig Wiglesworth and Pedersen, {Lars Egholm} and Galster, {Gorm Aske Gram Krohn}",

year = "2014",

month = oct,

day = "9",

language = "English",

volume = "90",

journal = "Physical Review C",

issn = "2469-9985",

publisher = "American Physical Society",

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TY - JOUR

T1 - Measurement of long-range pseudorapidity correlations and azimuthal harmonics in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector

AU - Aad, G.

AU - Abbott, B.

AU - Abdallah, J.

AU - Abdel-Khalek, S.

AU - Abdinov, O.

AU - Dam, Mogens

AU - Hansen, Jørn Dines

AU - Hansen, Jørgen Beck

AU - Xella, Stefania

AU - Hansen, Peter Henrik

AU - Petersen, Troels Christian

AU - Thomsen, Lotte Ansgaard

AU - Mehlhase, Sascha

AU - Jørgensen, Morten Dam

AU - Pingel, Almut Maria

AU - Løvschall-Jensen, Ask Emil

AU - Alonso Diaz, Alejandro

AU - Monk, James William

AU - Wiglesworth, Graig

AU - Pedersen, Lars Egholm

AU - Galster, Gorm Aske Gram Krohn

PY - 2014/10/9

Y1 - 2014/10/9

N2 - 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 (|Δϕ|<π/3) and back-to-back pairs (|Δφ|>2π/3) over the transverse momentum range 0.4T<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 νn as a function of pT and event activity. The extracted νn values for n=2 to 5 decrease with n. The ν2 and ν3 values are found to be positive in the measured pT range. The ν1 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 ν2 (pT), ν3 (pT), and ν4 (pT) are compared to the νn 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.

AB - 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 (|Δϕ|<π/3) and back-to-back pairs (|Δφ|>2π/3) over the transverse momentum range 0.4T<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 νn as a function of pT and event activity. The extracted νn values for n=2 to 5 decrease with n. The ν2 and ν3 values are found to be positive in the measured pT range. The ν1 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 ν2 (pT), ν3 (pT), and ν4 (pT) are compared to the νn 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.

M3 - Journal article

SN - 2469-9985

VL - 90

JO - Physical Review C

JF - Physical Review C

M1 - 044906

ER -

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

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