Finite size of hadrons and HBT interferometry for hydrodynamic sources

Abstract

Hadrons formed in heavy-ion collisions are not point-like objects, they cannot occupy too close space-time points. When the two bosons are too close to each other, their constituents start to mix and they cannot be considered as bosons subjected to Bose–Einstein statistics, this effect is called the excluded volume effect. We study the excluded volume effect on Hanbury Brown–Twiss (HBT) for the sources with various sizes. The effect on HBT was shown in out, side and long directions, and it is more obvious for the source with a narrow space-time distribution. The correlation functions for high transverse momenta are more suppressed by the excluded volume effect.