QCD equation of state and hadron resonance gas

• DOI: 10.1016/j.nuclphysa.2010.02.015
• Publication Date: 2010-03-21T08:13:13Z
• Authors: Pasi Huovinen; Péter Petreczky
• Keywords: Nuclear Theory; High Energy Physics - Lattice (hep-lat); FOS: Physical sciences; 01 natural sciences; Nuclear Theory (nucl-th); High Energy Physics - Phenomenology; High Energy Physics - Lattice; High Energy Physics - Phenomenology (hep-ph); 0103 physical sciences; Nuclear Experiment (nucl-ex); Nuclear Experiment

31 pages, LaTeX, 17 figures, typos corrected, references added<br/>We compare the trace anomaly, strangeness and baryon number fluctuations calculated in lattice QCD with expectations based on hadron resonance gas model. We find that there is a significant discrepancy between the hadron resonance gas and the lattice data. This discrepancy is largely reduced if the hadron spectrum is modified to take into account the larger values of the quark mass used in lattice calculations as well as the finite lattice spacing errors. We also give a simple parametrization of QCD equation of state, which combines hadron resonance gas at low temperatures with lattice QCD at high temperatures. We compare this parametrization with other parametrizations of the equation of state used in hydrodynamical models and discuss differences in hydrodynamic flow for different equations of state.<br/>