A. Bazavov, Tanmoy Bhattacharya, C. E. DeTar, H. -T. Ding, Steven Gottlieb, Rajan Gupta, P. Hegde, Urs Heller, F. Karsch, E. Laermann, L. Levkova, Swagato Mukherjee, P. Petreczky, Christian Schmidt, R. A. Soltz, W. Soeldner, R. Sugar, Pavlos M. Vranas
We calculate the quadratic fluctuations of net baryon number, electric charge and strangeness as well as correlations among these conserved charges in (2+1)-flavor lattice QCD at zero chemical potential. Results in the continuum limit are obtained using calculations with tree level improved gauge and the highly improved staggered quark (HISQ) actions with almost physical light and strange quark masses at three different values of the lattice cut-off. We compare our results with the hadron resonance gas (HRG) model calculations and find agreement with HRG model results only for temperatures T < 150 MeV. We observe significant deviations in the temperature range 160 MeV < T < 170 MeV and qualitative differences in the behavior of the three conserved charge sectors. At $T \simeq 160 MeV$ quadratic net baryon number fluctuations in QCD agree with HRG model calculations while, the net electric charge fluctuations in QCD are about 10% smaller and net strangeness fluctuations are about 20% larger. These findings are relevant to the discussion of freeze-out conditions in relativistic heavy ion collisions.
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http://arxiv.org/abs/1203.0784
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