Chemical Equilibration and Transport Properties of Hadronic Matter near $T_c$

Abstract

We discuss how the inclusion of Hagedorn states near $T_c$ leads to short chemical equilibration times of proton anti-proton pairs, $K\bar{K}$ pairs, and $\Lambda \bar{\Lambda }$ pairs, which indicates that hadrons do not need to be "born" into chemical equilibrium in ultrarelativistic heavy ion collisions. We show that the hadron ratios computed within our model match the experimental results at RHIC very well. Furthermore, estimates for $\eta /s$ near $T_c$ computed within our resonance gas model are comparable to the string theory viscosity bound $\eta /s=1/4\pi$. Our model provides a good description of the recent lattice results for the trace anomaly close to $T_c=196$ MeV.

4 pages, 3 figures, to appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennessee

References in corpus (9)

• Viscosity in Strongly Interacting Quantum Field Theories from Black Hole Physics
• The QCD Equation of State with almost Physical Quark Masses
• Equation of state and QCD transition at finite temperature
• Chemical freeze-out in ultra-relativistic heavy ion collisions at sqrt(s)_NN = 130 and 200 GeV
• Shear viscosity of a hadronic gas mixture
• Fast Equilibration of Hadrons in an Expanding Fireball
• Particle Ratios as a Probe of the QCD Critical Temperature
• Universal chemical freeze-out as a phase transition signature
• Chemical Equilibration at the Hagedorn Temperature

Cited by in corpus (5)

• Hadron Mass Spectrum and the Shear Viscosity to Entropy Density Ratio of Hot Hadronic Matter
• Dynamics of Chemical Equilibrium of Hadronic Matter Close to $T_c$
• Elliptic Flow Suppression due to Hadron Mass Spectrum
• Hagedorn States and Thermalization
• Hagedorn States and Thermalization in Heavy Ion Collisions