Observation of Long-Range Elliptic Azimuthal Anisotropies in s√=13 and 2.76 TeV pp Collisions with the ATLAS Detector - Université Clermont Auvergne Accéder directement au contenu
Article Dans Une Revue Physical Review Letters Année : 2016

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

G. Aad (1) , S. Albrand (2) , J. Collot (2) , S. Crépé-Renaudin (2) , P.A. Delsart (2) , C. Gabaldon (2) , M.H. Genest (2) , J.Y. Hostachy (2) , F. Ledroit-Guillon (2) , A. Lleres (2) , A. Lucotte (2) , F. Malek (2) , C. Monini (2) , J. Stark (2) , B. Trocmé (2) , M. Wu (2) , G. Rahal (3) , Z. Barnovska (4) , N. Berger (4) , M. Delmastro (4) , L. Di Ciaccio (4) , S. Elles (4) , C. Goy (4) , T. Hryn’ova (4) , S. Jézéquel (4) , I. Koletsou (4) , R. Lafaye (4) , J. Leveque (4) , N. Massol (4) , P. Mastrandrea (4) , G. Sauvage (4) , E. Sauvan (1) , O. Simard (4) , T. Todorov (4) , E. Yatsenko (4) , I. Wingerter-Seez (4) , M.K. Ayoub (5) , A. Bassalat (5) , C. Bécot (5) , S. Binet (5) , C. Bourdarios (5) , D. Delgove (5) , J-B. de Vivie De Regie (5) , L. Duflot (5) , M. Escalier (5) , L. Fayard (5) , D. Fournier (5) , E.L. Gkougkousis (5) , J-F. Grivaz (5) , T. Guillemin (5) , F. Hariri (5) , S. Henrot-Versille (5) , J. Hrivnac (5) , L. Iconomidou-Fayard (5) , M. Kado (5) , A. Lounis (5) , N. Makovec (5) , N. Morange (5) , C. Nellist (5) , P. Petroff (5) , L. Poggioli (5) , P. Puzo (5) , A. Renaud (5) , D. Rousseau (5) , G. Rybkin (5) , A.C. Schaffer (5) , E. Scifo (5) , L. Serin (5) , S. Simion (5) , R. Tanaka (5) , D. Zerwas (5) , Zhongkai Zhang (5) , Y. Zhao (5) , L. Alio (1) , M. Barbero (1) , Y. Coadou (1) , C. Diaconu (1) , Sara Diglio (1) , F. Djama (1) , O. Duccu (1) , L. Feligioni (1) , J. Gao (1) , G.D. Hallewell (1) , F. Hubaut (1) , S.J. Kahn (1) , E. B. F. G. Knoops (1) , E. Le Guirriec (1) , J. Liu (1) , K. Liu (1) , D. Madaffari (1) , K. Mochizuki (1) , E. Monnier (1) , S. Muanza (1) , Y. Nagai (1) , E. Nagy (1) , P. Pralavorio (1) , A. Rozanov (1) , T. Serre (1) , M. Talby (1) , R.E. Ticse Torres (1) , E. Tiouchichine (1) , S. Tisserant (1) , J. Toth (1) , F. Touchard (1) , L. Vacavant (1) , D. Boumediene (6) , E. Busato (6) , D. Calvet (6) , S. Calvet (6) , J. Donini (6) , E. Dubreuil (6) , G. Gilles (6) , Ph. Gris (6) , H. Liao (6) , R. Madar (6) , D. Pallin (6) , S.M. Romano Saez (6) , C. Santoni (6) , D. Simon (6) , T. Theveneaux-Pelzer (6) , F. Vazeille (6)
G. Aad
N. Berger
C. Goy
T. Hryn’ova
D. Rousseau
Y. Coadou
S. Calvet

Résumé

ATLAS has measured two-particle correlations as a function of relative azimuthal-angle, $\Delta \phi$, and pseudorapidity, $\Delta \eta$, in $\sqrt{s}$=13 and 2.76 TeV $pp$ collisions at the LHC using charged particles measured in the pseudorapidity interval $|\eta|$<2.5. The correlation functions evaluated in different intervals of measured charged-particle multiplicity show a multiplicity-dependent enhancement at $\Delta \phi \sim 0$ that extends over a wide range of $\Delta\eta$, which has been referred to as the "ridge". Per-trigger-particle yields, $Y(\Delta \phi)$, are measured over 2<$|\Delta\eta|$<5. For both collision energies, the $Y(\Delta \phi)$ 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 $\cos{(2\Delta \phi)}$. The fitted Fourier coefficient, $v_{2,2}$, exhibits factorization, suggesting that the ridge results from per-event $\cos{(2\phi)}$ 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 $p_{\mathrm{T}}$ 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.
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Dates et versions

in2p3-01200692 , version 1 (07-09-2023)

Identifiants

Citer

G. Aad, S. Albrand, J. Collot, S. Crépé-Renaudin, P.A. Delsart, et al.. Observation of Long-Range Elliptic Azimuthal Anisotropies in s√=13 and 2.76 TeV pp Collisions with the ATLAS Detector. Physical Review Letters, 2016, 116, pp.172301. ⟨10.1103/PhysRevLett.116.172301⟩. ⟨in2p3-01200692⟩
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