Michał Szymański

The investigation of QCD with heavier than physical quark masses provides a valuable insight into the physics of deconfinement. In the infinite quark mass limit, deconfinement is a first-order phase transition, linked to the spontaneous breaking of the Z(3) symmetry. Dynamical quarks break this symmetry explicitly and, when sufficiently light, deconfinement turns into a second-order phase transition. The Polyakov loop serves as an order parameter and additional information can be obtained from its susceptibilities. However, these quantities are renormalization-scheme dependent, and thus it is important to investigate other deconfinement-sensitive observables as well. In this talk, I will focus on the net-baryon number fluctuations. In an effective Polyakov loop model, I demonstrate that the ratio of fourth- to second-order cumulants approaches a step-function behavior as the quark masses increase, which suggests that this quantity remains an excellent probe of deconfinement even in the large quark mass limit. Additionally, I will discuss the scaling properties of the baryon number cumulants at the deconfinement critical point for both zero and non-zero densities. By employing a Landau-type potential, the mean-field critical exponents are extracted and numerically confirmed. I also predict the full critical exponents using the scaling function approach.