Nonequilibrium time evolution of higher order cumulants of conserved charges and event-by-event analysis

TL;DR

This paper studies how higher order cumulants of conserved charges evolve over time in a diffusive medium, highlighting their potential to reveal the dynamical history of hot matter in heavy ion collisions.

Contribution

It introduces a diffusion master equation approach to analyze the time evolution of higher order cumulants in relativistic heavy ion collisions.

Findings

Fourth-order cumulant of net-electric charge is suppressed at LHC energies.

Rapidity window dependence of cumulants can trace the medium's evolution.

Higher order cumulants provide insights into the hadronization process.

Abstract

We investigate the time evolution of higher order cumulants of conserved charges in a volume with the diffusion master equation. Applying the result to the diffusion of non-Gaussian fluctuations in the hadronic stage of relativistic heavy ion collisions, we show that the fourth-order cumulant of net-electric charge at LHC energy is suppressed compared with the recently observed second-order cumulant at ALICE, if the higher order cumulants at hadronization are suppressed compared with their values in the hadron phase in equilibrium. The significance of the experimental information on the rapidity window dependence of various cumulants in investigating the history of the dynamical evolution of the hot medium created in relativistic heavy ion collisions is emphasized.