Lattice QCD results on cumulant ratios at freeze-out

16th International Conference on Strangeness in Quark Matter

Karsch, Frithjof^1,2

Fakultät für Physik, Universität Bielefeld, Bielefeld

D-33615, Germany^1

Physics Department, Brookhaven National Laboratory, Upton

NY

11973, United States^2

关键词: Baryon chemical potential;    Charge fluctuations;    Equation of state;    Freeze out temperature;    Hadron resonance gas;    Model calculations;    Number fluctuations;    Skellam distributions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/779/1/012015/pdf
DOI  :  10.1088/1742-6596/779/1/012015

来源: IOP

【 摘 要 】

Ratios of cumulants of net proton-number fluctuations measured by the STAR Collaboration show strong deviations from a skellam distribution, which should describe thermal properties of cumulant ratios, if proton-number fluctuations are generated in equilibrium and a hadron resonance gas (HRG) model would provide a suitable description of thermodynamics at the freeze-out temperature. We present some results on 6thorder cumulants entering the calculation of the QCD equation of state at non-zero values of the baryon chemical potential (μB) and discuss limitations on the applicability of HRG thermodynamics deduced from a comparison between QCD and HRG model calculations of cumulants of conserved charge fluctuations. We show that basic features of the μB-dependence of skewness and kurtosis ratios of net proton-number fluctuations measured by the STAR Collaboration resemble those expected from a QCD calculation of the corresponding net baryon-number cumulant ratios.