Hydrodynamic models have been notoriously successful in modeling ultrarelativistic nucleus-nucleus collisions. They describe the quark-gluon plasma locally as a system in thermal equilibrium, boosted with the fluid velocity. The transverse boost increases the transverse momenta (pt) of heavier particles, and results in a specific mass ordering of pt spectra. I introduce a systematic procedure to extract the distribution of the fluid velocity from pt spectra, by fitting them as a superposition of boosted thermal distributions. This approach generalizes blast-wave fits, which are commonly used in the field. We apply it to LHC data on Pb-Pb collisions at 2.76 TeV. I discuss the differences between this approach and an actual hydrodynamic calculation.
This talk is based on https://arxiv.org/abs/2012.07898 in collaboration with Anthony Guillen.
Jiangyong Jia