Different Realizations of Cooper-Frye Sampling with Conservation Laws

Abstract

Approaches based on viscous hydrodynamics for the hot and dense stage and hadronic transport for the final dilute rescattering stage are successfully applied to the dynamic description of heavy ion reactions at high beam energies. One crucial step in such hybrid approaches is the so called particlization, the transition between the hydrodynamic description to microscopic degrees of freedom. For this purpose, individual particles are sampled on the Cooper-Frye hypersurface. In this work, 4 different realizations of sampling algorithms are compared, where three of them incorporate global conservation laws of quantum numbers in each event. The algorithms are compared within two types of scenarios: simple "box" hypersurface consisting of only one static cell and a typical particlization hypersurface for Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV. For all algorithms the mean multiplicities (or particle spectra) remain unaffected by global conservation laws in the case of large volumes. In contrast, the fluctuations of the particle numbers are affected considerably. The fluctuations of the newly developed SPREW algorithm based on exponential weights and the recently suggested SER algorithm based on ensemble rejection are smaller than without conservation laws and agree with the expectation from the canonical ensemble. The previously applied mode sampling algorithm produces dramatically larger fluctuations, than it is expected in the corresponding microcanonical ensemble, and therefore should be avoided in fluctuation studies. This study might be of interest for investigations of particle fluctuations and correlations, e.g. the suggested signatures for a phase transition or a critical endpoint, in hybrid approaches that are affected by global conservation laws.

11 pages, 8 figures, version accepted to publication in Journal of Physics G

References in corpus (11)

• 200 A GeV Au+Au collisions serve a nearly perfect quark-gluon liquid
• Fully integrated transport approach to heavy ion reactions with an intermediate hydrodynamic stage
• Space-time evolution of bulk QCD matter
• Constraining the Eq. of State of Super-Hadronic Matter from Heavy-Ion Collisions
• Estimation of the shear viscosity at finite net-baryon density from A+A collision data at $\sqrt{s_{\mathrm{NN}}}=7.7-200$ GeV
• Quantifying properties of hot and dense QCD matter through systematic model-to-data comparison
• Analytical and numerical Gubser solutions of the second-order hydrodynamics
• Longitudinal Decorrelation of Anisotropic Flows in Heavy-ion Collisions at the CERN Large Hadron Collider
• Event simulation based on three-fluid hydrodynamics for collisions at energies available at the Dubna Nuclotron-based Ion Collider Facility and at the Facility for Antiproton and Ion Research in Darmstadt
• Charge conservation and the shape of the ridge of two-particle correlations in relativistic heavy-ion collisions
• Multiplicity Distributions in Canonical and Microcanonical Statistical Ensembles

Cited by in corpus (3)

• Multi-particle and charge-dependent azimuthal correlations in heavy-ion collisions at the Relativistic Heavy-Ion Collider
• Particlization of an interacting hadron resonance gas with global conservation laws for event-by-event fluctuations in heavy-ion collisions
• Non-critical fluctuations of (net) charges and (net) protons from iEBE-VISHNU hybrid model