Equation of state and QCD transition at finite temperature

作者：Alexei Bazavov, Tanmoy Bhattacharya, M. Cheng, Norman H. Christ, C. DeTar, Shinji Ejiri, Steven Gottlieb, Rajan Gupta, Urs M. Heller, Kay Huebner, Chulwoo Jung, F. Karsch, E. Laermann, L. Levkova, Chuan Miao, Robert D. Mawhinney, Péter Petreczky, Christian Schmidt, R. A. Soltz, W. Soeldner, R. Sugar, D. Toussaint, Pavlos Vranas · 发表于：Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields · 年份：2009 · DOI：10.1103/physrevd.80.014504 · 被引用次数：580 · 研究领域：High-Energy Particle Collisions Research、Particle physics theoretical and experimental studies、Quantum Chromodynamics and Particle Interactions

We calculate the equation of state in $2+1$ flavor QCD at finite temperature with physical strange quark mass and almost physical light quark masses using lattices with temporal extent ${N}_{\ensuremath{\tau}}=8$. Calculations have been performed with two different improved staggered fermion actions, the asqtad and p4 actions. Overall, we find good agreement between results obtained with these two $O({a}^{2})$ improved staggered fermion discretization schemes. A comparison with earlier calculations on coarser lattices is performed to quantify systematic errors in current studies of the equation of state. We also present results for observables that are sensitive to deconfining and chiral aspects of the QCD transition on ${N}_{\ensuremath{\tau}}=6$ and 8 lattices. We find that deconfinement and chiral symmetry restoration happen in the same narrow temperature interval. In an appendix we present a simple parametrization of the equation of state that can easily be used in hydrodynamic model calculations. In this parametrization we include an estimate of current uncertainties in the lattice calculations which arise from cutoff and quark mass effects.