Aad, G;
Abbott, B;
Abdallah, J;
Abdinov, O;
Aben, R;
Abolins, M;
AbouZeid, OS;
... Zwalinski, L; + view all
(2016)
Observation of Long-Range Elliptic Azimuthal Anisotropies in root s=13 and 2.76 TeV pp Collisions with the ATLAS Detector.
Physical Review Letters
, 116
(17)
, Article 172301. 10.1103/PhysRevLett.116.172301.
![[thumbnail of PhysRevLett.116.172301.pdf]](https://discovery-pp.ucl.ac.uk/style/images/fileicons/text.png) |
Text
PhysRevLett.116.172301.pdf - Published Version Available under License : See the attached licence file. Download (580kB) |
Abstract
ATLAS has measured two-particle correlations as a function of the relative azimuthal angle, Δϕ, and pseudorapidity, Δη, in sqrt[s]=13 and 2.76 TeV pp collisions at the LHC using charged particles measured in the pseudorapidity interval |η|<2.5. The correlation functions evaluated in different intervals of measured charged-particle multiplicity show a multiplicity-dependent enhancement at Δϕ∼0 that extends over a wide range of Δη, which has been referred to as the "ridge." Per-trigger-particle yields, Y(Δϕ), are measured over 2<|Δη|<5. For both collision energies, the Y(Δϕ) distribution in all multiplicity intervals is found to be consistent with a linear combination of the per-trigger-particle yields measured in collisions with less than 20 reconstructed tracks, and a constant combinatoric contribution modulated by cos(2Δϕ). The fitted Fourier coefficient, v_{2,2}, exhibits factorization, suggesting that the ridge results from per-event cos(2ϕ) modulation of the single-particle distribution with Fourier coefficients v_{2}. The v_{2} values are presented as a function of multiplicity and transverse momentum. They are found to be approximately constant as a function of multiplicity and to have a p_{T} dependence similar to that measured in p+Pb and Pb+Pb collisions. The v_{2} values in the 13 and 2.76 TeV data are consistent within uncertainties. These results suggest that the ridge in pp collisions arises from the same or similar underlying physics as observed in p+Pb collisions, and that the dynamics responsible for the ridge has no strong sqrt[s] dependence.
| Type: | Article |
|---|---|
| Title: | Observation of Long-Range Elliptic Azimuthal Anisotropies in root s=13 and 2.76 TeV pp Collisions with the ATLAS Detector |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/PhysRevLett.116.172301 |
| Publisher version: | http://doi.org/10.1103/PhysRevLett.116.172301 |
| Language: | English |
| Additional information: | Copyright © 2016 CERN, for the ATLAS Collaboration. All rights reserved. This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. |
| Keywords: | Science & Technology, Physical Sciences, Physics, Multidisciplinary, Physics, Proton-proton Collisions, Angular-correlations, Flow, Multiplicity, Dependence, Energy, Side |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1495024 |
Archive Staff Only
 |
View Item |
