An effective macroscopic description of early-stage chemical equilibration in high-energy heavy-ion collisions
Abstract
The early stage of high-energy heavy-ion collisions undergoes transient dynamics, evolving non-perturbatively from a gluon-rich to a chemically equilibrated quark-gluon plasma. We develop an effective hydrodynamic approach that casts the microscopic quark equilibration dynamics as the relaxation evolution of an effective macroscopic bulk viscous pressure. The evolution of this effective bulk viscous pressure captures quark chemical equilibration and the breaking of conformal symmetry, thereby providing a smooth onset of the lattice QCD equation of state after a few fm/c in the hydrodynamic evolution. We investigate phenomenological effects of this macroscopic description on final-state observables in Pb+Pb, O+O, and p+Pb collisions at the Large Hadron Collider.
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BibTeX
@misc{akbarov2026effective,
title = {{An effective macroscopic description of early-stage chemical equilibration in high-energy heavy-ion collisions}},
author = {Anar Akbarov and Hendrik Roch and Chun Shen},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10284},
eprint = {2610.10284},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.10284},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - An effective macroscopic description of early-stage chemical equilibration in high-energy heavy-ion collisions
AU - Anar Akbarov
AU - Hendrik Roch
AU - Chun Shen
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.10284
UR - https://arxiv.org/abs/2610.10284
AB - The early stage of high-energy heavy-ion collisions undergoes transient dynamics, evolving non-perturbatively from a gluon-rich to a chemically equilibrated quark-gluon plasma. We develop an effective hydrodynamic approach that casts the microscopic quark equilibration dynamics as the relaxation evolution of an effective macroscopic bulk viscous pressure. The evolution of this effective bulk viscous pressure captures quark chemical equilibration and the breaking of conformal symmetry, thereby providing a smooth onset of the lattice QCD equation of state after a few fm/c in the hydrodynamic evolution. We investigate phenomenological effects of this macroscopic description on final-state observables in Pb+Pb, O+O, and p+Pb collisions at the Large Hadron Collider.
ER -