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arXiv · 2006.10169

Deconfinement and degrees of freedom in $pp$ and $A-A$ collisions at LHC energies

Aditya N Mishra·Guy Paić·C. Pajares·R. P. Scharenberg·B. K. Srivastava
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Abstract

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.

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Aditya N Mishra, Guy Paić, C. Pajares, R. P. Scharenberg, B. K. Srivastava. 2020-06-17. Deconfinement and degrees of freedom in $pp$ and $A-A$ collisions at LHC energies. https://doi.org/10.1140/epja/s10050-021-00552-2

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