Particlization in fluid dynamical simulations of heavy-ion collisions: The iS3D module

Mike McNelis, Derek Everett, Ulrich Heinz

Abstract: The iS3D particlization module simulates the emission of hadrons from heavy-ion collisions via Monte-Carlo sampling of the Cooper–Frye formula which converts fluid dynamical information into local phase-space distributions for hadrons. The code package includes multiple choices for the non-equilibrium correction to these distribution functions: the 14-moment approximation, first-order Chapman–Enskog expansion, and two types of modified equilibrium distributions. This makes it possible to explore to what extent heavy-ion experimental data are sensitive to different choices for δfn, presently the main source of theoretical uncertainty in the particlization stage. We validate our particle sampler with a high degree of precision by generating several million hadron emission events from a longitudinally boost-invariant hypersurface and comparing the event-averaged particle spectra and space–time distributions to the Cooper–Frye formula.Program summaryProgram Title: iS3DCPC Library link to program files: http://dx.doi.org/10.17632/n2cxrjgkwr.1Licensing provisions: GPLv3Programming Language: C++, CUDA CExternal routines/libraries: GNU Scientific Library (GSL)Nature of problem: Sampling the emission of hadrons during the particlization stage of heavy-ion collisions and accelerating the continuous Cooper–Frye formula.Solution method: Monte-Carlo simulation, parallel computing