Dr Lance Labun (University of Texas, Austin)
Locating the QCD critical point is the goal of several major heavy ion collision experiments, and it may be possible to see signatures of critical behaviour in event-by-event fluctuations of conserved charges. We show characteristic peaks in the third $\chi_3$ and fourth $\chi_4$ fluctuation moments of baryon number as a function of chemical potential (or center of mass energy) and how they depend on proximity of freeze out to the critical point. In a model independent analysis, we explain qualitative features of the moments' dependence on chemical potential and temperature near the critical point, and we identify a few signatures, such as relative location of the $\chi_3$ and $\chi_4$ peaks, expected to be robust. Using the Gross Neveu model we provide a quantitative example of these predictions, which may support experimental observations of a peak in $\chi_4$ as a signature of the critical point.