Anisotropy Scaling Functions in Heavy-Ion Collisions: Insights into the `Ultra-Central Flow Puzzle' and Constraints on Transport Coefficients and Nuclear Deformation

Roy A. Lacey

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arXiv · 2402.09389

Anisotropy Scaling Functions in Heavy-Ion Collisions: Insights into the `Ultra-Central Flow Puzzle' and Constraints on Transport Coefficients and Nuclear Deformation

Roy A. Lacey

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Abstract

Anisotropy scaling functions derived from comprehensive measurements of transverse momentum- and centrality-dependent anisotropy coefficients $v_2(p_T,\text{cent})$ and $v_3(p_T,\text{cent})$ in Pb+Pb collisions at 5.02 and 2.76 TeV, Xe+Xe collisions at 5.44 TeV and Au+Au collisions at 0.2 TeV, offer new insights into the `ultra-central flow puzzle.' These functions integrate diverse measurements into a single curve, clarifying anisotropy attenuation throughout the entire $p_T$ and centrality range. They reveal the influence of initial-state eccentricities ($\varepsilon_{n}$), dimensionless size ($\mathbb{R}$), radial flow, viscous correction to the thermal distribution function ($δ_f$), the medium's stopping power ($\Hat{q}$), and specific shear viscosity ($η/s$) on the observed anisotropies. This analysis not only enhances understanding of transport coefficients but also provides crucial constraints on nuclear deformation.

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Roy A. Lacey. 2024-09-16. Anisotropy Scaling Functions in Heavy-Ion Collisions: Insights into the `Ultra-Central Flow Puzzle' and Constraints on Transport Coefficients and Nuclear Deformation. https://arxiv.org/abs/2402.09389

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