PUB - Publikationen an der Universität Bielefeld

We calculate the quadratic fluctuations of net baryon number, electric chargeand strangeness as well as correlations among these conserved charges in(2+1)-flavor lattice QCD at zero chemical potential. Results in the continuumlimit are obtained using calculations with tree level improved gauge and thehighly improved staggered quark (HISQ) actions with almost physical light andstrange quark masses at three different values of the lattice cut-off. Wecompare our results with the hadron resonance gas (HRG) model calculations andfind agreement with HRG model results only for temperatures T < 150 MeV. Weobserve significant deviations in the temperature range 160 MeV < T < 170 MeVand qualitative differences in the behavior of the three conserved chargesectors. At $T \simeq 160 MeV$ quadratic net baryon number fluctuations in QCDagree with HRG model calculations while, the net electric charge fluctuationsin QCD are about 10% smaller and net strangeness fluctuations are about 20%larger. These findings are relevant to the discussion of freeze-out conditionsin relativistic heavy ion collisions.