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Non-Gibbs Particle Spectra from Thermal Equilibrium

T. S. Biro·G. Gyorgyi·A. Jakovac·G. Purcsel
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Abstract

We propose that transverse momentum spectra with power-law tails observed in ultrarelativistic heavy ion collisions can be interpreted as originating in a medium in thermal equilibrium. General conditions on the dynamical equations are formulated, leading in equilibrium to various energy distributions of particles. Starting with the linear Fokker-Planck equation we analyze conditions for Boltzmann-Gibbs, Tsallis, or other equilibrium distributions based upon the dependence of fluctuation and dissipation on the energy of the observed subsystem. RHIC neutral pion data definitely exclude Boltzmann-Gibbs distribution over the entire range of observed transverse momenta.

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T. S. Biro, G. Gyorgyi, A. Jakovac, G. Purcsel. 2004-09-14. Non-Gibbs Particle Spectra from Thermal Equilibrium. https://arxiv.org/abs/hep-ph/0409157

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