Chemical and thermal freeze-out parameters from1Ato200AGeV

The present knowledge about hadrons produced in relativistic heavy ion collisions is compatible with chemical freeze-out happening when the energy density divided by the particle density reaches the value of 1 GeV. This observation is used to determine the energy dependence of the chemical freeze-out parameters $T_{\mathrm{ch}}$ and ${\mu }_B^{\mathrm{ch}}$ for beam energies varying between 1 and $200A$ GeV. The consequences of this energy dependence are studied for various particle ratios. Predictions for particle ratios at beam energy $40A$ GeV are presented. The conditions for thermal freeze-out are also determined. These correspond either to an energy density of 45 ${\mathrm{M}\mathrm{e}\mathrm{V}/\mathrm{f}\mathrm{m}}^3$ or to a particle density of $0.05/{\mathrm{fm}}^3.$