Reconstructing the final state of Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV

Abstract

We fit the single-hadron transverse-momentum spectra measured in Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV with the blast-wave model that includes production via resonance decays. Common fit to pions, kaons, (anti)protons, and lambdas yields centrality dependence of the freeze-out temperature and transverse expansion velocity. In the most central collisions we see $T=98$ MeV and $⟨v_t⟩=0.654$. The $K^{\ast }$ resonance fits into this picture but the $\varphi$ meson might freeze-out a little earlier. Multistrange baryons seem to decouple at higher temperature and weaker transverse flow. Within our model we observe hints of chemical potential for the charged pions.

Comments: accepted version (some explanations added with respect to v1), 21 pages, 12 figures