Influence of resonance decays on triangular flow in heavy-ion collisions

Anisotropic flow in relativistic collisions of heavy-ions yields important information about the state of the hot and dense matter created in the collision. Study of triangular flow in Pb+Pb collisions at LHC was performed using HYDJET++ Monte Carlo generator. HYDJET++ combines both hydrodynamics-driven soft part together with hard jet-part, giving a realistic prediction for vast number of hadron species. The model also enables study of influence of final-state interactions on flow of created hadrons. Triangular flow patterns of pions, kaons and protons were studied. We found that resonance decays influence significantly the shape of the distributions

Higher harmonics of azimuthal anisotropy in relativistic heavy ion collisions in HYDJET++ model

The LHC data on azimuthal anisotropy harmonics from PbPb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted in the framework of the HYDJET++ model. The cross-talk of elliptic $v_2$ and triangular $v_3$ flow in the model generates both even and odd harmonics of higher order. Comparison with the experimental data shows that this mechanism is able to reproduce the $p_{\rm T}$ and centrality dependencies of quadrangular flow $v_4$, and also the basic trends for pentagonal $v_5$ and hexagonal $v_6$ flows.Comment: 12 pages including 13 figures as EPS-files; prepared using LaTeX package for publication in the European Physical Journal

Elliptic flow studies using the CMS detector

The azimuthal anisotropy of charged particles in heavy ion collisions is an important probe of quark-gluon plasma evolution at early stages. The nuclear reaction plane can be determined independently by different detector subsystems and using different analysis methods. This paper reports the capability of the CMS detector at the LHC to reconstruct the reaction plane of the collision and to me asure elliptic flow with calorimetry and a tracking system. The analysis is based on a full CMS detector simulation of \rm{Pb+Pb} events with the HYDJET event generator

Influence of jets and resonance decays on the constituent quark scaling of elliptic flow

The Monte Carlo HYDJET++ model, that contains both hydrodynamic state and jets, is applied to study the influence of the interplay between soft and hard processes on the formation of the elliptic flow in heavy-ion collisions at RHIC and LHC energies. Jets are found to cease the hydro-like increase of the elliptic flow with rising p_T. Since jets are more influential at LHC than at RHIC, the v_2 at LHC should be weaker than that at RHIC. Violation of the number-of-constituent-quark (NCQ) scaling is predicted. The decays of resonances are found to enhance the low-p_T part of the elliptic flow of pions and light baryons, and work toward the fulfillment of the NCQ scaling.Comment: 6 pages, talk given at the International Conference on Strangeness in Quark Matter 2009 (SQM09

Towards the centrality dependence description of the charge balance function in the HYDJET++ model

Data from the Large Hadron Collider on the charge balance function in Pb+Pb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted within the framework of the HYDJET++ model. This model allows us to reproduce the experimentally observed centrality dependence of the balance function widths at the relatively low transverse momentum intervals qualitatively due to the different charge creation mechanisms in soft and hard processes. However, the fully adequate description of the balance function in these intervals implies the essential model modification by including the exact charge conservation in terms of the canonical ensemble instead of the grand canonical one. A procedure is proposed for introducing charge correlations into the thermal model without changing other model parameters. With increasing transverse momenta, the default model results describe experimental data much better because the contribution from the soft component of the model is significantly reduced in these transverse momentum intervals. In practice, there is a transition to a single source of charge correlations, namely, charge correlations in jets for which the exact charge conservation takes place at each stage.Comment: REVTEX, 8 pages, 6 figure