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Abstract

We present measurement of elliptic flow, v 2, for charged and identified particles at midrapidity in Au+Au collisions at $\sqrt {s_{NN} } $ = 7.7–39 GeV. We compare the inclusive charged hadron v 2 to those from transport model calculations, such as the UrQMD model, AMPT default model and AMPT string-melting model. We discuss the energy dependence of the difference in v 2 between particles and anti-particles. The v 2 of ϕ meson is observed to be systematically lower than other particles in Au+Au collisions at $\sqrt {s_{NN} } $ = 11.5 GeV.

Abstract

We present the results on elliptic flow with multi-strange baryons produced in Pb-Pb collisions at $\sqrt {s_{NN} } $ = 2.76 TeV. The analysis is performed with the ALICE detector at LHC. Multi-strange baryons are reconstructed via their decay topologies and the v 2 measurements are analyzed with the two-particle scalar product method. The p T differential v 2 values are compared to the viscous hydrodynamical (VISH2+1) model calculation and to the STAR measurements in Au-Au collisions at $\sqrt {s_{NN} } $ = 200 GeV. We found that the model describes ≡ and Ωv 2 measurements within uncertainties. The differential v 2 of ≡ and Ω is similar to the STAR measurements at 200 GeV in Au-Au collisions.

Abstract

The interplay between spectator and participant matter in heavy-ion collisions is investigated within the isospin-dependent quantum molecular dynamics (IQMD) model in terms of the rapidity distribution of light charged particles. The effect of different types and sizes of rapidity distributions is studied in elliptical flow. The elliptical-flow patterns show the important role of nearby spectator matter on the participant zone. This role is further explained on the basis of the passing time of the spectator and the expansion time of the participant zone. The transition from in-plane to out-of-plane emission is observed only when the mid-rapidity region is included into the rapidity bin. Otherwise no transition occurs. The transition energy is found to be highly sensitive to the size of the rapidity bin, while it is only weakly dependent on the type of the rapidity distribution. These theoretical findings are found to be in agreement with experimental results.

Abstract

In this proceeding, we briefly describe the viscous hydrodynamics + hadron cascade hybrid model VISHNU for relativistic heavy ion collisions and report the current status on extracting the QGP viscosity from elliptic flow data.

Abstract

The first part of the beam energy scan (BES) program at RHIC was successfully completed in the years 2010 and 2011. First STAR results from particle yield measurements are in good agreement with previously published data from SPS and AGS experiments whereas other results like azimuthal HBT and K/π event-by-event fluctuations differ at some energies. In addition, new observations like the centrality dependence of chemical freeze-out parameters (T ch and µB) or the smoothly increasing difference with decreasing energy in the elliptic flow v 2 between particles and corresponding anti-particles, are discussed.

, the energy dissipated by jets can also alter the properties of bulk nuclear matter (for instance, so-called elliptic flow) in the intermediate transverse momentum range. There is little understanding of such effects. For such studies, we need to efficiently model the soft particle evolution with a high spatial resolution to capture the jet-induced modification of the characteristics of the bulk nuclear matter. Moreover, the Cartesian coordinate system is preferred to ensure a high spatial resolution that is constant throughout the evolution of the system. Such

without crossflow to compare to a numerical simulation using the time-averaged Navier-Stokes equations and a finite volume approach including the SIMPLE algorithm to study the fountain flows with and without crossflow and the jet velocity characteristics with a crossflow. Fairweather e i a l . 191 engage a finite difference scheme for solving the three-dimensional elliptic flow equations, while Rudman /11/ uses a piecewise parabolic method in a finite volume approach tc model the single jet in a crossflow. Menon and Rizk 15/ implement a Large- Eddy simulation

pertinent physicochemical properties of the five fuels are presented in Table 1. 3 Development of the Computer Model 3.1. General Formulation The quasi-2-D combustion model is essentially composed of stream tubes (zones) of flowing air, unburned spray, and combustion products surrounding a central recirculating zone (CTRZ), as shown in Figure 2. The number of external stream tubes (zones) may vary from one (the simplest case) to five or more. The size of the CTRZ is determined by Allison's axi- symmetric gas phase elliptic flow code. The amount of mass

the near inlet region. Four different types of inlet profiles in the usual manner were tested, and the mea- sured inlet profile was shown to yield the best flowfield prediction. Among three assumed inlet boundary conditions, the prediction obtained with the plug-flow-type profiles is less satisfactory than the other two. The prediction obtained with a real computation of fully-developed-flow profiles does not improve much than that obtained with the empirical formulae suggested by Khalil. This could be due to the exclusion of.the influence of the real elliptic

does not improve much than that obtained with the em- pirical formulae suggested by Khalil. This could be due to the exclusion of the influence of the real elliptic flow in the expansion at the exit planes of the inner and annual tubes on the computation of inlet boundary conditions of Case 2. Effect of turbulent Schmidt number on com- putation of mass transport is also examined and is found less significant than the effect stemming from the employed inlet boundary conditions. 23 Additional Information to Reviewers Three mesh systems: 32x28, 36x32 and 40x