Pion freeze-out as seen through HBT correlations in heavy ion collisions from FAIR/AGS to RHIC energies

作者：Li Qingfeng^*; Bleicher Marcus; Stoecker Horst

来源：Journal of Physics G: Nuclear and Particle Physics , 2007, 34(9): 2037-2044.

DOI：10.1088/0954-3899/34/9/012

We perform a systematic analysis of several HBT parameters in heavy ion collisions from E-beam = 2 A GeV to v root s(NN) = 200 GeV within the UrQMD transport approach and compare the results to experimental data where available. We find that the ' lifetime' of the emission source as calculated from tau similar to root R-O(2) - R-S(2) is larger than the experimentally observed values at all investigated energies. The calculated volume of the pion source ( V-f) is found to increase monotonously with increasing beam energy, and the experimentally observed decrease of the measured Vf at AGS is not seen. Finally, we calculate the mean free path lambda(f) = 0.5 - 1 fm of pions at freeze- out and find a good description of the experimental data above the AGS energy region, supporting the suggestion of a universal kinetic decoupling criterion up to the highest RHIC energies.

• 出版日期2007-9