PUB - Publikationen an der Universität Bielefeld

We calculate cumulants of fluctuations of net-baryon number, net-electriccharge and net-strangeness, in the framework of lattice regularized QCD. We usea highly improved staggered quark (HISQ) action on lattices with temporalextent of N_tau=6,8 and 12 and almost physical quark masses. By means of aTaylor expansion in various chemical potentials and under demanding bothstrangeness neutrality as well as the correct isospin asymmetry, we evaluatethese fluctuations at conditions met in heavy ion collisions. Cumulants ofnet-electric charge fluctuations can, in principle, also be measured in heavyion experiments. We therefore propose a method to extract freeze-outparameters, such as the freeze-out temperature and baryon chemical potential,based on a comparison of lattice results and experimental measurements of twodifferent ratios of net-electric charge cumulants. As this method involves only(lattice) QCD results and experimental measurements it is model independentand, for the purpose of extracting freeze-out parameters, does not require anyinput from hadron resonance gas model calculations.