Centrality dependence ofπ,K, andpproduction in Pb-Pb collisions atsNN=2.76TeV

In this paper measurements are presented of ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, ${K}^{\ifmmode\pm\else\textpm\fi{}}$, $p$, and $\overline{p}$ production at midrapidity ($|y|<0.5$), in Pb-Pb collisions at $\sqrt{{s}_{NN}}=2.76$ TeV as a function of centrality. The measurement covers the transverse-momentum (${p}_{T}$) range from 100, 200, and 300 MeV/$c$ up to 3, 3, and 4.6 GeV/$c$ for $\ensuremath{\pi}$, $K$, and $p$, respectively. The measured ${p}_{T}$ distributions and yields are compared to expectations based on hydrodynamic, thermal and recombination models. The spectral shapes of central collisions show a stronger radial flow than measured at lower energies, which can be described in hydrodynamic models. In peripheral collisions, the ${p}_{T}$ distributions are not well reproduced by hydrodynamic models. Ratios of integrated particle yields are found to be nearly independent of centrality. The yield of protons normalized to pions is a factor $\ensuremath{\sim}$1.5 lower than the expectation from thermal models.

Centrality dependence ofπ,K, andpproduction in Pb-Pb collisions atsNN=2.76TeV | Litlas