EQUATION OF STATE, SPECTRA, AND COMPOSITION OF HOT AND DENSE INFINITEHADRONIC MATTER IN A MICROSCOPIC TRANSPORT MODEL

Equilibrium properties of infinite relativistic hadron matter are inve stigated using the ultrarelativistic quantum molecular dynamics (UrQMD ) model. The simulations are performed in a box with periodic boundary conditions. Equilibration times depend critically on energy and baryo n densities. Energy spectra of various hadronic species are shown to b e isotropic and consistent with a single temperature in equilibrium. T he variation of energy density versus temperature shows a Hagedorn-lik e behavior with a limiting temperature of 130 +/- 10 MeV. Comparison o f abundances of different particle species to ideal hadron gas model p redictions show good agreement only if detailed balance is implemented for all channels. At low energy densities, high mass resonances are n ot relevant; however, their importance rises with increasing energy de nsity. The relevance of these different conceptual frameworks for any interpretation of experimental data is questioned.