Comparision of the Pion Emission Function in Hadron-hadron and Heavy-ion Collisions

Combining results on single-particle distributions with those of the Bose-Einstein correlation analysis in the same experiment, the space-time emission function is extracted as a function of time and longitudinal coordinate, as well as a function of transverse coordinates. While the former function resembles a boomerang for both types of collision (only shifted in the time direction due to the larger freeze-out time in heavy-ion collisions), the latter function is Gaussian for heavy-ion collisions, but ring-shaped for hadron-hadron collisions.