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Title: Measurements of azimuthal anisotropy and charged-particle multiplicity in d + Au collisions at s NN = 200 , 62.4, 39, and 19.6 GeV

Here, we present measurements of the elliptic flow ( v 2 ) as a function of transverse momentum ( p T ), pseudorapidity ( η ), and centrality in d + Au collisions at √ s NN = 200 , 62.4, 39, and 19.6 GeV. The beam-energy scan of d + Au collisions provides a testing ground for the onset of flow signatures in small collision systems. We measure a nonzero v 2 signal at all four collision energies, which, at midrapidity and low p T , is consistent with predictions from viscous hydrodynamic models. Comparisons with calculations from parton transport models (based on the ampt Monte Carlo generator) show good agreement with the data at midrapidity to forward ( d -going) rapidities and low p T . At backward (Au-going) rapidities and p T > 1.5 GeV / c , the data diverges from ampt calculations of v 2 relative to the initial geometry, indicating the possible dominance of nongeometry related correlations, referred to as nonflow. We also present measurements of the charged-particle multiplicity ( d N ch / d η ) as a function of η in central d + Au collisions at the same energies. We findmore » that in d + Au collisions at √ s NN = 200 GeV the v 2 scales with d N ch / d η over all η in the PHENIX acceptance. At √ s NN = 62.4 , and 39 GeV, v 2 scales with d N ch / d η at midrapidity and forward rapidity, but falls off at backward rapidity. This is thus a departure from the d N ch / d η scaling may be a further indication of nonflow effects dominating at backward rapidity.« less
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Publication Date:
Report Number(s):
LA-UR-17-27785
Journal ID: ISSN 2469-9985; PRVCAN; TRN: US1800912
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 96; Journal Issue: 6; Journal ID: ISSN 2469-9985
Publisher:
American Physical Society (APS)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC). Nuclear Physics (NP) (SC-26); USDOE
Contributing Orgs:
PHENIX Collaboration
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; Atomic and Nuclear Physics
OSTI Identifier:
1416308
Alternate Identifier(s):
OSTI ID: 1414854