Strangeness production in heavy ion collisions at finite baryon number density

We study the K+/π+ and K-/π- production rates in heavy ion collisions, using a hadron gas model which includes baryon repulsion and intermediate resonances, taking strangeness conservation into account. In such a description, the state of the system is specified by its temperature T and its baryon number density nB. Fixing the K+/π+ and K-/π- rates then determines the freeze-out values of T and nB. The production rates recently measured in silicon-gold collisions at the Brookhaven AGS energies are shown to give 93 ≤ T ≤ 112 MeV and 0.02 ≤ nB ≤ 0.12 baryons/fm3. © 1990.