Cumulants of conserved charges in hydrodynamic simulations

We introduce a fast and simple method of computing cumulants of net-proton or net-charge fluctuations in event-by-event hydrodynamic simulations of heavy-ion collisions. One evaluates the mean numbers of particles in every hydrodynamic event. Cumulants are then expressed as a function of these mean numbers. We implement the corrections due to global conservation laws. The method is tested using ideal hydrodynamic simulations of Au+Au collisions at N/sNN = 200A GeV with the NeXSPheRIO code. Results are in good agreement with experimental data on net-proton and net-charge fluctuations by the STAR Collaboration.

Automated summary

We propose a fast and simple method for computing cumulants of net-proton or net-charge fluctuations in event-by-event hydrodynamic simulations of heavy-ion collisions. The method calculates the mean numbers of particles in each hydrodynamic event and expresses cumulants as a function of these mean numbers, while accounting for global conservation laws. Testing with ideal hydrodynamic simulations of Au+Au collisions at N/sNN = 200A GeV using the NeXSPheRIO code, the results show good agreement with experimental data on net-proton and net-charge fluctuations by the STAR Collaboration.