Particle Ratios at CERN, BNL and GSI : Unified Description of Freeze-Out Parameters

It is shown that the chemical freeze-out parameters obtained at CERN/SPS, BNL/AGS and GSI/SIS energies all correspond to a unique value of 1 GeV for the average energy per hadron.Comment: 4 pages, 3 Postscript figures, uses espcrc1.sty

THERMUS -- A Thermal Model Package for ROOT

THERMUS is a package of C++ classes and functions allowing statistical-thermal model analyses of particle production in relativistic heavy-ion collisions to be performed within the ROOT framework of analysis. Calculations are possible within three statistical ensembles; a grand-canonical treatment of the conserved charges B, S and Q, a fully canonical treatment of the conserved charges, and a mixed-canonical ensemble combining a canonical treatment of strangeness with a grand-canonical treatment of baryon number and electric charge. THERMUS allows for the assignment of decay chains and detector efficiencies specific to each particle yield, which enables sensible fitting of model parameters to experimental data.Comment: to be published in Computer Physics Communication

Van der Waals Excluded Volume Model of Multicomponent Hadron Gas

A generalization of the Van der Waals excluded volume procedure for the multicomponent hadron gas is proposed. The derivation is based on the grand canonical partition function for the system of particles of several species interacting by hard core potentials. The obtained formulae for thermodynamical quantities are consistent with underlying principles of statistical mechanics as well as with thermodynamical identities. The model can be applied to the analysis of experimental data for particle number ratios in relativistic nucleus-nucleus collisions.Comment: 8 page