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

Autor: Jiro Murata, Norbert Novitzky, Mate Csanad, Toru Sugitate, Ron Soltz, Ming Liu, Yaroslav Berdnikov, Michael Tannenbaum, Vladimir Khachatryan, Pavel Radzevich, Itzhak Tserruya, Christine Nattrass, Tetsuya Murakami, Abhisek Sen, Sandor Lokos, Dmitry Kotov, Krista Smith, Klaus Dehmelt, Yuji Goto, David Silvermyr, Victor Riabov, Andrey Yanovich, Wesley Metzger, Kenneth Read, Kyoichiro Ozawa, Prakhar Garg, Sergey Fokin, Xuan Li, Deepali Sharma, Hiroyuki Sako, Joe Osborn, Sourav Tarafdar, Jin Huang, Aleksandr Berdnikov, Arbin Timilsina, Kiyoshi Tanida, Kenta Shigaki
Rok vydání: 2017
Předmět:
Zdroj: Physical Review C. 96
ISSN: 2469-9993
2469-9985
DOI: 10.1103/physrevc.96.064905
Popis: We present measurements of the elliptic flow (v2) as a function of transverse momentum (pT), pseudorapidity (η), and centrality in d+Au collisions at sNN=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 v2 signal at all four collision energies, which, at midrapidity and low pT, 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 pT. At backward (Au-going) rapidities and pT>1.5GeV/c, the data diverges from ampt calculations of v2 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 (dNch/dη) as a function of η in central d+Au collisions at the same energies. We find that in d+Au collisions at sNN=200 GeV the v2 scales with dNch/dη over all η in the PHENIX acceptance. At sNN=62.4, and 39 GeV, v2 scales with dNch/dη at midrapidity and forward rapidity, but falls off at backward rapidity. This departure from the dNch/dη scaling may be a further indication of nonflow effects dominating at backward rapidity.
Databáze: OpenAIRE
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