Nonlinear hydrodynamic response confronts LHC data

Li Yan (1) , Subrata Pal (2) , Jean-Yves Ollitrault (1)

1 IPHT - Institut de Physique Théorique - UMR CNRS 3681
2 Department of Nuclear and Atomic Physics

Higher order harmonic flow $v_n$ (with $n\ge4$) in heavy-ion collisions can be measured either with respect to their own plane, or with respect to a plane constructed using lower-order harmonics. By assuming that higher flow harmonics are the superposition of medium nonlinear and linear responses to initial anisotropies, we propose a set of nonlinear response coefficients $\chi_n$'s, which are independent of initial state by construction. In experiments, $\chi_n$'s can be extracted as the ratio between higher order harmonic flow measured in the plane constructed by $v_2$ and $v_3$, and moments of lower order harmonic flow. Simulations with single-shot hydrodynamics and AMPT model lead to results of these nonlinear response coefficients in good agreement with the experimental data at the LHC energy. Predictions for $v_7$ and $v_8$ measured with respect to plane of lower order harmonics are given accordingly.

Keywords: Harmonic flow; nonlinear hydrodynamics response; heavy-ion collisions

Domains: Physics [physics]; Nuclear Theory [nucl-th]; Physics [physics]; Nuclear Experiment [nucl-ex]

Li Yan, Subrata Pal, Jean-Yves Ollitrault. Nonlinear hydrodynamic response confronts LHC data. Nuclear Physics A, 2015. ⟨cel-01323526⟩