L. Bravina, B. H. Brusheim Johansson, G. Eyyubova, E. Zabrodin
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.
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http://arxiv.org/abs/1302.6441
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