Azimuthal dependence of two-particle transverse momentum current correlations

Niseem Magdy; Sumit Basu; Victor Gonzalez; Ana Marin; Olga Evdokimov; Roy A. Lacey; Claude Pruneau

doi:10.1140/epjc/s10052-021-09568-w

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2021) 81: 779
https://doi.org/10.1140/epjc/s10052-021-09568-w

Regular Article - Experimental Physics

Azimuthal dependence of two-particle transverse momentum current correlations

Niseem Magdy¹^a, Sumit Basu², Victor Gonzalez³, Ana Marin⁴, Olga Evdokimov¹, Roy A. Lacey⁵ and Claude Pruneau³

¹ Department of Physics, University of Illinois at Chicago, 60607, Chicago, IL, USA
² Division of Particle Physics, Department of Physics, Lund University, Box 118, 221 00, Lund, Sweden
³ Department of Physics and Astronomy, Wayne State University, 48201, Detroit, MI, USA
⁴ Research Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
⁵ Department of Chemistry, State University of New York, 11794, Stony Brook, NY, USA

^a niseemm@gmail.com

Received: 18 May 2021
Accepted: 23 August 2021
Published online: 30 August 2021

Abstract

Two-particle transverse momentum correlation functions are a powerful technique for understanding the dynamics of relativistic heavy-ion collisions. Among these, the transverse momentum correlator $G_{2} (Δ η, Δ φ)$ $G_{2}\left( \varDelta \eta ,\varDelta \varphi \right)$ is of particular interest for its potential sensitivity to the shear viscosity per unit of entropy density $η / s$ $\eta /s$ of the quark-gluon plasma formed in heavy-ion collisions. We use the UrQMD, AMPT, and EPOS models for Au–Au at $\sqrt{s_{NN}}$ $\sqrt{s_\mathrm{NN}}$ = 200 GeV and Pb–Pb at $\sqrt{s_{NN}}$ $\sqrt{s_\mathrm{NN}}$ = 2760 GeV to investigate the long range azimuthal dependence of $G_{2} (Δ η, Δ φ)$ $G_{2}\left( \varDelta \eta ,\varDelta \varphi \right)$ , and explore its utility to constrain $η / s$ $\eta /s$ based on charged particle correlations. We find that the three models yield quantitatively distinct transverse momentum Fourier harmonics coefficients $a_{n}^{p_{T}}$ $a^{p_\mathrm{T}}_{n}$ . We also observe these coefficients exhibit a significant dependence on $η / s$ $\eta /s$ in the context of the AMPT model. These observations suggest that exhaustive measurements of the dependence of $G_{2} (Δ φ)$ $G_{2}\left( \varDelta \varphi \right)$ with collision energy, system size, collision centrality, in particular, offer the potential to distinguish between different theoretical models and their underlying assumptions. Exhaustive analyses of $G_{2} (Δ φ)$ $G_{2}\left( \varDelta \varphi \right)$ obtained in large and small systems should also be instrumental in establishing new constraints for precise extraction of $η / s$ $\eta /s$ .

© The Author(s) 2021

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