Pion source parameters in Ar on KCl collisions

Abstract
The space-time structure of the pion-emitting source for central collisions of Ar on KCl at 1.5 GeV/nucleon is studied. The fireball is found to be nearly spherical with a radius R=4.9±0.5 fm. No significant dependence on pion multiplicity is present. A dependence on pion energy is observed.