Bose - Einstein Correlations for Longitudinally Expanding , Finite Systems

Bose-Einstein correlations and momentum distributions are calculated for a longitudinally expanding boson source, where the expanding system has a finite size in space-time rapidity. Such systems are physically realized in any of the single jets in high energy e + e − , lepton-hadron and hadron-hadron collisions as well as in high energy heavy ion collisions, where the projectile is not really heavy. The 1D expansion generates a thermal length-scale in the longitudinal direction, which together with the finite length of the expanding tube effects both the momentum distribution and the Bose-Einstein correlation function. The Bose-Einstein correlations are shown to be more sensitive to the smaller, while the momentum distribution to the longer of the two longitudinal length-scales.