Out-Of-Equilibrium Transverse Momentum Spectra of Pions at LHC Energies

Abstract

In order to characterize the transverse momentum spectra (pT) of positive pions measured in the ALICE experiment, two thermal approaches are utilized; one is based on degeneracy of nonperfect Bose-Einstein gas and the other imposes an ad hoc finite pion chemical potential. The inclusion of missing hadron states and the out-of-equilibrium contribute greatly to the excellent characterization of pion production. An excellent reproduction of these pT-spectra is achieved at μπ=0.12 GeV and this covers the entire range of pT. The excellent agreement with the experimental results can be understood as a manifestation of not-yet-regarded anomalous pion production, which likely contributes to the long-standing debate on “anomalous” proton-to-pion ratios at top RHIC and LHC energies.