Observation of Long-Range Elliptic Azimuthal Anisotropies in √s=13 and 2.76 TeV pp Collisions with the ATLAS Detector

G Aad; B Abbott; J Abdallah; O Abdinov; R Aben; M Abolins; OS Abouzeid; H Abramowicz; H Abreu; R Abreu; Y Abulaiti; BS Acharya; L Adamczyk; DL Adams; J Adelman; S Adomeit; T Adye; AA Affolder; T Agatonovic-Jovin; J Agricola; JA Aguilar-Saavedra; SP Ahlen; F Ahmadov; G Aielli; H Akerstedt; TPA Åkesson; AV Akimov; GL Alberghi; J Albert; S Albrand; MJ Alconada Verzini; M Aleksa; IN Aleksandrov; C Alexa; G Alexander; T Alexopoulos; M Alhroob; G Alimonti; L Alio; J Alison; SP Alkire; BMM Allbrooke; PP Allport; A Aloisio; A Alonso; F Alonso; C Alpigiani; A Altheimer; B Alvarez Gonzalez; D Álvarez Piqueras; MG Alviggi; BT Amadio; K Amako; Y Amaral Coutinho; C Amelung; D Amidei; SP Amor Dos Santos; A Amorim; S Amoroso; N Amram; G Amundsen; C Anastopoulos; LS Ancu; N Andari; T Andeen; CF Anders; G Anders; JK Anders; KJ Anderson; A Andreazza; V Andrei; S Angelidakis; I Angelozzi; P Anger; A Angerami; F Anghinolfi; AV Anisenkov; N Anjos; A Annovi; M Antonelli; A Antonov; J Antos; F Anulli; M Aoki; L Aperio Bella; G Arabidze; Y Arai; JP Araque; ATH Arce; FA Arduh; JF Arguin; S Argyropoulos; M Arik; AJ Armbruster; O Arnaez; H Arnold; M Arratia; O Arslan; A Artamonov; G Artoni

Journal article

Observation of Long-Range Elliptic Azimuthal Anisotropies in √s=13 and 2.76 TeV pp Collisions with the ATLAS Detector

G Aad, B Abbott, J Abdallah, O Abdinov, R Aben, M Abolins, OS Abouzeid, H Abramowicz, H Abreu, R Abreu, Y Abulaiti, BS Acharya, L Adamczyk, DL Adams, J Adelman, S Adomeit, T Adye, AA Affolder, T Agatonovic-Jovin, J Agricola Show all

Physical Review Letters | Published : 2016

DOI: 10.1103/PhysRevLett.116.172301

Abstract

ATLAS has measured two-particle correlations as a function of the relative azimuthal angle, Δφ, and pseudorapidity, Δη, in 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 yie..

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University of Melbourne Researchers

Federico Scutti Author

Elisabetta Barberio Author

Matteo Volpi Author

G. N. Taylor Author

Grants

Awarded by European Commission

Funding Acknowledgements

We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZS, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TAEK, Turkey; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, the Canada Council, CANARIE, CRC, Compute Canada, FQRNT, and the Ontario Innovation Trust, Canada; EPLANET, ERC, FP7, Horizon 2020 and Marie Sklodowska-Curie Actions, European Union; Investissements d'Avenir Labex and Idex, ANR, Region Auvergne and Fondation Partager le Savoir, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF; BSF, GIF and Minerva, Israel; BRF, Norway; the Royal Society and Leverhulme Trust, United Kingdom. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN and the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (UK) and BNL (USA) and in the Tier-2 facilities worldwide.