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In most heavy ion collision simulations involving relativistic hydrodynamics, the Cooper-Frye formula is applied to transform the hydrodynamical fields to particles. In this article the so-called negative contributions in the Cooper-Frye formula are studied using a coarse-grained transport approach. The magnitude of negative contributions is investigated as a function of hadron mass, collision energy in the range of $E_{rm lab} = 5$--$160A$ GeV, collision centrality and the energy density transition criterion defining the hypersurface. The microscopic results are compared to negative contributions expected from hydrodynamical treatment assuming local thermal equilibrium. The main conclusion is that the number of actual microscopic particles flying inward is smaller than the negative contribution one would expect in an equilibrated scenario. The largest impact of negative contributions is found to be on the pion rapidity distribution at midrapidity in central collisions. For this case negative contributions in equilibrium constitute 8--13% of positive contributions depending on collision energy, but only 0.5--4% in cascade calculation. The dependence on the collision energy itself is found to be non-monotonous with a maximum at 10-20$A$ GeV.
Many models of heavy ion collisions employ relativistic hydrodynamics to describe the system evolution at high densities. The Cooper-Frye formula is applied in most of these models to turn the hydrodynamical fields into particles. However, the number
We investigate the baryonic contributions to the dilepton yield in high energy heavy ion collisions within the context of a transport model. The relative contribution of the baryonic and mesonic sources are examined. It is observed that most dominant
This report summarizes the presentations and discussions during the Rapid Reaction Task Force Dynamics of critical fluctuations: Theory -- phenomenology -- heavy-ion collisions, which was organized by the ExtreMe Matter Institute EMMI and held at GSI
We investigate the charged particle spectra produced in the heavy-ion collisions at nine centralities from different systems, i.e., Pb+Pb at $sqrt{s_{NN}}=2.76$ TeV and 5.02 TeV as well as Xe+Xe at $sqrt{s_{NN}}=5.44$ TeV, at Large Hadron Collider (L
We present a simple description of the energy density profile created in a nucleus-nucleus collision, motivated by high-energy QCD. The energy density is modeled as the sum of contributions coming from elementary collisions between localized charges