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), $\sqrt{s}=200$ $A$ GeV and $\sqrt{s}=2.76$ $A$ TeV, respectively. It is shown that the quenched jets contribute to the soft part of the $v_2\left(p_T\right)$ and $v_4\left(p_T\right)$ 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 $p_T\le 2$ 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.

• Received 2 January 2013

DOI:https://doi.org/10.1103/PhysRevC.87.034901