We discuss the role of cumulants of net baryon number fluctuations in the analysis of critical behavior in QCD and the study of freeze-out conditions in heavy ion experiments. Through the comparison of the current set of measurements of higher order cumulants of net baryon number fluctuations with lattice QCD calculations and results from hadron resonance gas model we can learn to what extent freeze-out as, determined by such cumulants, occurs close to the QCD transition temperature and thus can probe critical behavior at small values of the baryon chemical potential. However, we provide indications that a recently performed comparison of lattice QCD results on cumulants with data from heavy ion experiments suffer from systematic as well as statistical uncertainties in the lattice QCD calculations, which makes such comparison at present not useful.

• Received 15 July 2011

DOI:https://doi.org/10.1103/PhysRevD.84.051504