QCD equation of state with 2+1 flavors of improved staggered quarks (original) (raw)

We report results for the interaction measure, pressure and energy density for nonzero temperature QCD with 2+1 flavors of improved staggered quarks. In our simulations we use a Symanzik improved gauge action and the Asqtad O(a2)O(a^2)O(a2) improved staggered quark action for lattices with temporal extent Nt=4N_t=4Nt=4 and 6. The heavy quark mass msm_sms is fixed at approximately the physical strange quark mass and the two degenerate light quarks have masses mudapprox0.1msm_{ud}\approx0.1 m_smudapprox0.1ms or 0.2ms0.2 m_s0.2ms. The calculation of the thermodynamic observables employs the integral method where energy density and pressure are obtained by integration over the interaction measure.