Single-freeze-out model for ultra relativistic heavy-ion collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV and the LHC proton puzzle

Understand

The single-freeze-out model with parametrized hypersurface and flow geometry is employed to analyze the transverse-momentum spectra of hadrons produced in the Pb+Pb collisions at the collision energy of {$\sqrt{s_{\rm NN}}=2.76$ TeV} at the CERN Large Hadron Collider (LHC).

• With the notable exception for protons and antiprotons, we find a very good agreement between the model results and the data for the measured hadron species.
• The additional analysis of the HBT radii of pions helps us to select, from several different types of freeze-out studied in this work, the most realistic form of the freeze-out hypersurface.
• We find that discrepancy ratio between the model and experiment for the proton/antiproton spectra depends on $p_T$, dropping from 2 in the soft region to 1 around $p_T=1.5$ GeV.