### Abstract

ATLAS measurements of two-particle correlations are presented for s=5.02 and 13 TeV pp collisions and for sNN=5.02 TeV p+Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle Δφ, and pseudorapidity separation Δη, using charged particles detected within the pseudorapidity interval |η|<2.5. Azimuthal modulation in the long-range component of the correlation function, with |Δη|>2, is studied using a template fitting procedure to remove a "back-to-back" contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, cos(2Δφ), modulation observed in a previous measurement, the pp correlation functions exhibit significant cos(3Δφ) and cos(4Δφ) modulation. The Fourier coefficients vn,n associated with the cos(nΔφ) modulation of the correlation functions for n=2-4 are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with cos(nφ) modulation of per-event single-particle azimuthal angle distributions. The single-particle Fourier coefficients vn are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for n=2-4. The integrated luminosities used in this analysis are, 64 nb-1 for the s=13 TeV pp data, 170 nb-1 for the s=5.02 TeV pp data, and 28 nb-1 for the sNN=5.02 TeV p+Pb data.

Original language | English (US) |
---|---|

Article number | 024908 |

Journal | Physical Review C |

Volume | 96 |

Issue number | 2 |

DOIs | |

State | Published - Aug 22 2017 |

### Fingerprint

### ASJC Scopus subject areas

- Nuclear and High Energy Physics

### Cite this

*Physical Review C*,

*96*(2), [024908]. https://doi.org/10.1103/PhysRevC.96.024908

Research output: Contribution to journal › Article

*Physical Review C*, vol. 96, no. 2, 024908. https://doi.org/10.1103/PhysRevC.96.024908

}

TY - JOUR

T1 - Measurements of long-range azimuthal anisotropies and associated Fourier coefficients for pp collisions at s =5.02 and 13 TeV and p+Pb collisions at sNN =5.02 TeV with the ATLAS detector MEASUREMENTS of LONG-RANGE AZIMUTHAL ... M. AABOUD et al.

AU - Atlas Collaboration

AU - Aaboud, M.

AU - Aad, G.

AU - Abbott, B.

AU - Abdallah, J.

AU - Abdinov, O.

AU - Abeloos, B.

AU - Abouzeid, O. S.

AU - Abraham, N. L.

AU - Abramowicz, H.

AU - Abreu, H.

AU - Abreu, R.

AU - Abulaiti, Y.

AU - Acharya, B. S.

AU - Adachi, S.

AU - Adamczyk, L.

AU - Adams, D. L.

AU - Adelman, J.

AU - Adomeit, S.

AU - Adye, T.

AU - Affolder, A. A.

AU - Agatonovic-Jovin, T.

AU - Aguilar-Saavedra, J. A.

AU - Ahlen, S. P.

AU - Ahmadov, F.

AU - Aielli, G.

AU - Akerstedt, H.

AU - Åkesson, T. P.A.

AU - Akimov, A. V.

AU - Alberghi, G. L.

AU - Albert, J.

AU - Albrand, S.

AU - Alconada Verzini, M. J.

AU - Aleksa, M.

AU - Aleksandrov, I. N.

AU - Alexa, C.

AU - Alexander, G.

AU - Alexopoulos, T.

AU - Alhroob, M.

AU - Ali, B.

AU - Aliev, M.

AU - Alimonti, G.

AU - Alison, J.

AU - Alkire, S. P.

AU - Allbrooke, B. M.M.

AU - Allen, B. W.

AU - Cheu, Elliott C

AU - Johns, Kenneth A

AU - Rutherfoord, John P

AU - Shupe, Michael A

AU - Varnes, Erich W

PY - 2017/8/22

Y1 - 2017/8/22

N2 - ATLAS measurements of two-particle correlations are presented for s=5.02 and 13 TeV pp collisions and for sNN=5.02 TeV p+Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle Δφ, and pseudorapidity separation Δη, using charged particles detected within the pseudorapidity interval |η|<2.5. Azimuthal modulation in the long-range component of the correlation function, with |Δη|>2, is studied using a template fitting procedure to remove a "back-to-back" contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, cos(2Δφ), modulation observed in a previous measurement, the pp correlation functions exhibit significant cos(3Δφ) and cos(4Δφ) modulation. The Fourier coefficients vn,n associated with the cos(nΔφ) modulation of the correlation functions for n=2-4 are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with cos(nφ) modulation of per-event single-particle azimuthal angle distributions. The single-particle Fourier coefficients vn are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for n=2-4. The integrated luminosities used in this analysis are, 64 nb-1 for the s=13 TeV pp data, 170 nb-1 for the s=5.02 TeV pp data, and 28 nb-1 for the sNN=5.02 TeV p+Pb data.

AB - ATLAS measurements of two-particle correlations are presented for s=5.02 and 13 TeV pp collisions and for sNN=5.02 TeV p+Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle Δφ, and pseudorapidity separation Δη, using charged particles detected within the pseudorapidity interval |η|<2.5. Azimuthal modulation in the long-range component of the correlation function, with |Δη|>2, is studied using a template fitting procedure to remove a "back-to-back" contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, cos(2Δφ), modulation observed in a previous measurement, the pp correlation functions exhibit significant cos(3Δφ) and cos(4Δφ) modulation. The Fourier coefficients vn,n associated with the cos(nΔφ) modulation of the correlation functions for n=2-4 are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with cos(nφ) modulation of per-event single-particle azimuthal angle distributions. The single-particle Fourier coefficients vn are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for n=2-4. The integrated luminosities used in this analysis are, 64 nb-1 for the s=13 TeV pp data, 170 nb-1 for the s=5.02 TeV pp data, and 28 nb-1 for the sNN=5.02 TeV p+Pb data.

UR - http://www.scopus.com/inward/record.url?scp=85028862324&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85028862324&partnerID=8YFLogxK

U2 - 10.1103/PhysRevC.96.024908

DO - 10.1103/PhysRevC.96.024908

M3 - Article

VL - 96

JO - Physical Review C

JF - Physical Review C

SN - 2469-9985

IS - 2

M1 - 024908

ER -