Effect of jets on $v_4/v_2^2$ ratio and constituent quark scaling in relativistic heavy-ion collisions

TL;DR

This study uses the HYDJET++ model to analyze how jets influence the anisotropic flow ratios and quark scaling in heavy-ion collisions at RHIC and LHC energies, revealing jets' significant role in flow behavior and scaling violations.

Contribution

It demonstrates that jets affect flow ratios and violate NCQ scaling, providing a quantitative explanation for experimental observations at RHIC and LHC energies.

Findings

Jets increase v_4/v_2^2 ratio, deviating from ideal hydrodynamics predictions.

Jets contribute to the violation of NCQ scaling at LHC.

Jets explain the rise of the v_4/v_2^2 ratio at high transverse momentum.

Abstract

The Monte Carlo HYDJET++ model, that combines parametrized hydrodynamics with jets, is employed to study formation of second v_2 and fourth v_4 components of the anisotropic flow in ultrarelativistic heavy-ion collisions at energies of the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), sqrt{s}=200 AGeV and sqrt{s}=2.76 ATeV, respectively. It is shown that the quenched jets contribute to the soft part of the v_2(p_T) and v_4(p_T) spectra. The jets increase the ratio v_4/v_2^2 thus leading to deviations of the ratio from the value of 0.5 predicted by the ideal hydrodynamics. Together with the event-by-event fluctuations, the influence of jets can explain quantitatively the ratio v_4/v_2^2 at p_T < 2 GeV/c for both energies and qualitatively the rise of its high-p_T tail at LHC. Jets are also responsible for violation of the number-of-constituent-quark (NCQ) scaling at LHC despite the fact that the scaling is fulfilled for the hydro-part of particle spectra.