QCD critical point and experimental observables

Abstract

The presence of a critical point in the QCD phase diagram can deform the trajectories describing the evolution of the expanding fireball in the μB–T phase diagram. If the average emission time of hadrons is a function of transverse velocity, as microscopic simulations of the hadronic freeze-out dynamics suggest, the deformation of the hydrodynamic trajectories will change the transverse velocity (βT) dependence of the proton–antiproton ratio when the fireball passes in the vicinity of the critical point. An unusual βT-dependence of the ratio in a narrow beam energy window would thus signal the presence of the critical point.