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arXiv · 2505.14823

Relaxation Time Approximation for a multi-species relativistic gas

Gabriel S. Rocha·Gabriel S. Denicol
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Abstract

We generalize a recent prescription for the relaxation time approximation for the relativistic Boltzmann equation for systems with multiple particle species at finite temperature. This is performed by adding counter-terms to the traditional Anderson-Witting ansatz for each particle species. Our approach allows for the use of momentum-dependent relaxation times and the obedience of local conservation laws regardless of the definition of the local equilibrium state. As an application, we derive the first order Chapman-Enskog corrections to the equilibrium distribution and display results for the hadron-resonance gas. We also demonstrate that our collision term ansatz obeys the second law of thermodynamics.

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Gabriel S. Rocha, Gabriel S. Denicol. 2025-05-20. Relaxation Time Approximation for a multi-species relativistic gas. https://doi.org/10.1103/gzc4-lnzd

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