Exact baryon, strangeness, and charge conservation in hadronic gas models

Abstract

Relativistic heavy ion collisions are studied assuming that particles can be described by a hadron gas in thermal and chemical equilibrium. The exact conservation of baryon number, strangeness, and charge is explicitly taken into account. For heavy ions the effect arising from the neutron surplus becomes important and leads to a substantial increase in, e.g., the ${\ensuremath{\pi}}^{\ensuremath{-}}/{\ensuremath{\pi}}^{+}$ ratio. A method is developed which is suited to the study of small systems up to baryon number 20, which, unfortunately excludes cases like S-S.