Evolution of Charge Fluctuations and Correlations in the Hydrodynamic Stage of Heavy Ion Collisions

TL;DR

This paper investigates how charge fluctuations and correlations evolve during the hydrodynamic stage of heavy ion collisions, combining lattice gauge theory calculations with hydrodynamic simulations to compare with experimental data.

Contribution

It presents a novel integration of lattice gauge theory charge fluctuation calculations with hydrodynamic simulations to study charge correlation evolution in heavy ion collisions.

Findings

Results align with preliminary STAR measurements

Charge correlations evolve with time due to diffusion and fluctuation dynamics

Significant discrepancies suggest further model refinement needed

Abstract

Charge fluctuations for a baryon-neutral quark-gluon plasma have been calculated in lattice gauge theory. These fluctuations provide a well-posed rigorous representation of the quark chemistry of the vacuum for temperatures above T_c >~ 155 MeV. Due to the finite lifetime and spatial extent of the fireball created in relativistic heavy ion collisions, charge-charge correlations can only equilibrate for small volumes due to the finite time required to transport charge. This constraint leads to charge correlations at finite relative position that evolve with time. The source and evolution of such correlations is determined by the evolution of the charge fluctuation and the diffusion constant for light quarks. Here, calculations are presented for the evolution of such correlations superimposed onto hydrodynamic simulations. Results are similar to preliminary measurements from STAR, but significant discrepancies remain.