Proton number cumulants in heavy-ion collisions and the search for the QCD critical point

Abstract

The phase structure of QCD and the nature of the transition between ordinary hadronic matter and the deconfined state of quark-gluon plasma remain among the key open questions in high-energy physics. This talk will explore how these questions can be addressed using fluctuation observables, with a focus on event-by-event fluctuations in heavy-ion collisions and the search for the QCD critical point at finite baryon number density. I will discuss the dynamical description of proton number cumulants in heavy-ion collisions based on relativistic hydrodynamics, and the resulting constraints on the QCD critical point derived from recent data from the RHIC beam energy scan.