Nuclear Physics Seminar

Abstract: Mapping the phase diagram of QCD is one of the important goals of heavy-ion collision experiments. The key to unraveling the phase diagram lies in the thermal fluctuations in hydrodynamics which are sensitive to thermodynamic properties. This is elucidated by the fact that higher-order cumulants are sensitive probes of the QCD critical point. Freeze-out of fluctuations is a crucial step for connecting predictions of fluctuating hydrodynamics (such as, e.g., Hydro+) with experimental observations such as the measurements of the cumulants of proton multiplicities. The traditional Cooper-Frye freeze-out procedure doesn't provide a prescription for freeze-out of fluctuations. In this talk, I'll discuss a generalization to the Cooper-Frye freeze-out based on the principle of maximum entropy. The procedure determines the most likely ensemble of free streaming particles that is consistent with the conservation laws of energy-momentum and charges. I'll then compare this procedure to a previously used freeze-out framework based on a universal description near a critical point. Finally, I'll demonstrate the effects of critical slowing down on cumulants of proton multiplicities via the freeze-out of a simplified deterministic calculation of hydrodynamics with fluctuations.