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Title: Matching excluded-volume hadron-resonance gas models and perturbative QCD to lattice calculations

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Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 90; Journal Issue: 2; Journal ID: ISSN 0556-2813
American Physical Society
Country of Publication:
United States

Citation Formats

Albright, M., Kapusta, J., and Young, C. Matching excluded-volume hadron-resonance gas models and perturbative QCD to lattice calculations. United States: N. p., 2014. Web. doi:10.1103/PhysRevC.90.024915.
Albright, M., Kapusta, J., & Young, C. Matching excluded-volume hadron-resonance gas models and perturbative QCD to lattice calculations. United States. doi:10.1103/PhysRevC.90.024915.
Albright, M., Kapusta, J., and Young, C. Wed . "Matching excluded-volume hadron-resonance gas models and perturbative QCD to lattice calculations". United States. doi:10.1103/PhysRevC.90.024915.
title = {Matching excluded-volume hadron-resonance gas models and perturbative QCD to lattice calculations},
author = {Albright, M. and Kapusta, J. and Young, C.},
abstractNote = {},
doi = {10.1103/PhysRevC.90.024915},
journal = {Physical Review C},
number = 2,
volume = 90,
place = {United States},
year = {Wed Aug 27 00:00:00 EDT 2014},
month = {Wed Aug 27 00:00:00 EDT 2014}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevC.90.024915

Citation Metrics:
Cited by: 23works
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  • We compare the lattice results on QCD phase diagram for two and three flavors with the hadron resonance gas model (HRGM) calculations. Lines of constant energy density {epsilon} have been determined at different baryo-chemical potentials {mu}{sub B}. For the strangeness chemical potentials {mu}{sub S}, we use two models. In one model, we explicitly set {mu}{sub S}=0 for all temperatures and baryo-chemical potentials. This assignment is used in lattice calculations. In the other model, {mu}{sub S} is calculated in dependence on T and {mu}{sub B} according to the condition of vanishing strangeness. We also derive an analytical expression for the dependencemore » of T{sub c} on {mu}{sub B}/T by applying Taylor expansion of {epsilon}. In both cases, we compare HRGM results on T{sub c}-{mu}{sub B} diagram with the lattice calculations. The agreement is excellent, especially when the trigonometric function of {epsilon} is truncated up to the same order as done in lattice simulations. For studying the efficiency of the truncated Taylor expansion, we calculate the radius of convergence. For zero- and second-order radii, the agreement with lattice is convincing. Furthermore, we make predictions for QCD phase diagram for nontruncated expressions and physical masses. These predictions are to be confirmed by heavy-ion experiments and future lattice calculations with very small lattice spacing and physical quark masses.« less
  • We recapitulate a thermodynamically consistent excluded volume hadron gas model and examine its differences with other {open_quotes}thermal models{close_quotes} used in the literature. Preliminary experimental data for particle number ratios in the collisions of Au+Au at the BNL AGS (11AGeV/c) and Pb+Pb at the CERN SPS (160AGeV/c) are analyzed. For equal values of the hadron hard-core parameters the excluded volume model gives essentially the ideal gas predictions for the particle number ratios, which is similar to other thermal models. We observe, however, the systematic excess of experimental pion abundances compared to the ideal gas results. This effect can be explained inmore » our model by a smaller pion hard-core volume compared to those of other hadrons. The absolute values for particle number and energy densities at the chemical freezeout are predicted with a simultaneous fit to all these AGS and SPS particle number ratios. {copyright} {ital 1997} {ital The American Physical Society}« less
  • Multiplicity fluctuations are studied in the van der Waals excluded volume hadron-resonance gas model. The calculations are done in the grand canonical ensemble within the Boltzmann statistics approximation. The scaled variances for positive, negative, and all charged hadrons are calculated along the chemical freeze-out line of nucleus-nucleus collisions at different collision energies. The multiplicity fluctuations are found to be suppressed in the van der Waals gas. The numerical calculations are presented for two values of the hard-core hadron radius, r=0.3 and 0.5 fm, as well as for the upper limit of the excluded volume suppression effects.
  • The shear viscosity {eta} in the van der Waals excluded volume hadron-resonance gas model is considered. For the shear viscosity the result of a nonrelativistic gas of hard-core particles is extended to a mixture of particles with different masses but equal values of hard-core radius r. The relativistic corrections to hadron average momenta in thermal equilibrium are also taken into account. The ratio of the viscosity {eta} to the entropy density s is studied. It monotonically decreases along the chemical freeze-out line in nucleus-nucleus collisions with increasing collision energy. As a function of hard-core radius r, a broad minimum ofmore » the ratio {eta}/s{approx_equal}0.3 near r{approx_equal}0.5 fm is found at high collision energies. For the charge-neutral system at T=T{sub c}=180 MeV, a minimum of the ratio {eta}/s congruent with 0.24 is reached for r congruent with 0.53 fm. To justify a hydrodynamic approach to nucleus-nucleus collisions within the hadron phase the restriction from below, r{>=}0.2 fm, on the hard-core hadron radius should be fulfilled in the excluded volume hadron-resonance gas.« less