The process of Lévy walk, i.e., movement patterns described by heavy-tailed random walks, plays a role in various phenomena, from chemical and microbiological systems through marine predators to climate change. Recent experiments have suggested that this phenomenon also appears in heavy-ion collisions. In high-energy collisions of heavy nuclei, the strongly interacting Quark Gluon Plasma is created, which, similarly to the early Universe, undergoes a rapid expansion and transition back to hadronic matter. In the subsequent expanding hadron gas, particles interact until kinetic freeze-out, when their momenta stop changing, and they freely transition toward the detectors. Measuring spatial freeze-out distributions is a crucial tool in understanding the dynamics of the created matter and the interactions among its constituents. In this talk, we discuss related experimental findings and their simulation-based description[1]. Utilising Monte-Carlo simulations, we show step length distributions indeed lead to Lévy-stable distributions. We discuss several challenges this poses to the current understanding of observed particle distributions in high-energy physics.

 

[1]: Dániel Kincses, Márton Nagy, Máté Csanád: "Lévy walk of pions in heavy-ion collisions", Communications Physics 8, 55 (2025)