PUB - Publikationen an der Universität Bielefeld

We present a determination of freeze-out conditions in heavy-ion collisionsbased on ratios of cu- mulants of net electric charge fluctuations obtainedfrom lattice QCD. These ratios can reliably be calculated for a wide range ofchemical potential values by using a next-to-leading order Taylor seriesexpansion around the limit of vanishing baryon, electric charge and strangenesschemical potentials. We first determine the strangeness and electric chargechemical potentials that characterize the conditions in heavy ion collisions atRHIC and LHC. We then show that a comparison of lattice QCD results for ratiosof up to third order cumulants of electric charge fluctuations withexperimental results allows us to extract the freeze-out baryon chemicalpotential and the freeze-out temperature. We apply our method to preliminarydata of the STAR and PHENIX collaborations.