Statistical model description of K+ and K− production between 1–10 A·GeV

Abstract

The excitation functions of K + and K − mesons in heavy ion collisions are studied within a statistical model assuming chemical and thermal equilibrium with exact strangeness conservation. At low incident energies the associate production of kaons, i.e., the production of a K + together with a hyperon and the production of a K − together with a K +, implies specific features: different threshold energies and different dependences of K + and K − yields on baryon number density. It is shown that the experimentally observed equality of the K + and K − rates at energies s − s th ≤0 is due to a crossing of the two excitation functions. Furthermore, the independence of the K + to K − ratio on the number of participating nucleons observed at 1 and 10 A·GeV is consistent with this model.