We present the extraction of the temperature by analyzing the charged particle transverse momentum spectra in lead-lead (Pb-Pb) and proton-proton (${ \bf pp}$) collisions at LHC energies from the ALICE Collaboration using the Color String Percolation Model (CSPM). From the measured energy density ${ \bm \varepsilon}$ and the temperature T the dimensionless quantity ${ \bm \varepsilon/}T^{ 4}$ is obtained to get the degrees of freedom (DOF), ${ \bm \varepsilon}/T^{ 4}$ = DOF ${ \pi^{ 2}}$/30. We observe for the first time a two-step behavior in the increase of DOF, characteristic of deconfinement, above the hadronization temperature at temperature $\sim$ 210 MeV for both Pb-Pb and ${ \bf pp}$ collisions and a sudden increase to the ideal gas value of $\sim $ 47 corresponding to three quark flavors in the case of Pb-Pb collisions.
Categories: hep-ph hep-ex hep-th nucl-ex