Thermodynamical approach to few-body hadronic interactions

The purpose of the paper is to examine the thermodynamic model from the ratios of the single-pion production in a final three-body system relative to the two-body elastic and/or quasi-elastic cross-sections at comparatively low energies. It was found that there is a regularity for endothermic reactions for a certain range of energies. The ratio of cross-sections for positive-pion-proton interaction indicates the consistency of either choices for the universal temperature of the hadronic system T0=117 and 160 MeV. The similar ratio for the exthothermic reactions exhibit an irregular behaviour in the sense that they escape from the present simple theoretical formula. An additional test of the model is suggested. (author)