Speaker
Description
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) [1]. From the measured energy density ${\varepsilon}$ and the temperature T the dimensionless quantity ${ \varepsilon/}T^{4}$ is obtained to get the degrees of freedom (DOF), ${\varepsilon}/T^{4}$ = 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.
[1].M. A. Braun, J. Dias de~Deus, A. S. Hirsch, C. Pajares, R. P. Scharenberg, and B. K. Srivastava, Deconfinement and clustering of color sources in nuclear collisions, Phys. Rep. 599, 1 (2015).
