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Transport coefficients of strongly interacting quark-gluon plasma including elastic and inelastic scattering within the dynamical quasiparticle model

Gaia Ingrosso1,*, Olga Soloveva2,1,3, Ilia Grishmanovskii1, Taesoo Song2, and Elena Bratkovskaya2,1,3

  • *Contact author: ingrosso@itp.uni-frankfurt.de
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Phys. Rev. D 114, 056007 – Published 8 September, 2026

DOI: https://doi.org/10.1103/stk4-zk62

Abstract

We study the impact of inelastic gluon-radiation and absorption processes on the transport coefficients of the quark-gluon plasma within the dynamical quasiparticle model (DQPM) in the temperature–baryon-chemical-potential plane (T,μB). Extending the 2→2 baseline established in previous DQPM calculations, we include gluon-radiation 2→3 and the inverse gluon-absorption 3→2 scattering channels with massive partons and effective DQPM propagators and vertices. The corresponding momentum-dependent interaction rates and relaxation times are used to calculate the shear viscosity, bulk viscosity, electric conductivity, and baryon diffusion coefficient as functions of temperature T and baryon chemical potential μB. Within the relaxation time approximation, we find that 2↔3 contributions systematically reduce all considered transport coefficients relative to the 2→2 only results, in accordance with the decrease of the relaxation times. In the thermal regime explored here, however, this reduction remains moderate, since the investigated inelastic rates stay below the 2→2 ones over the considered (T,μB) range. The inelastic channels become more relevant mainly for partonic scatterings at large momenta, which are thermally suppressed in the strongly interacting QGP. At μB=0, the resulting η/s, ζ/s, and σQ/T are compatible with available lattice-QCD estimates within uncertainties. At finite μB, our results provide predictions for the transport properties of QCD matter relevant for beam-energy-scan programs.

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Phys. Rev. D 114, 056007– Published 8 September, 2026
  • Received 16 June 2026
  • Revised 5 August 2026
  • Accepted 11 August 2026
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