Early-times Yang-Mills dynamics and the characterization of strongly interacting matter with statistical learning

Abstract

In ultrarelativistic heavy-ion collisions, a plasma of deconfined quarks and gluons is formed within $1$ fm/c of the nuclei's impact. The complex dynamics of the collision before $\approx 1$ fm/c is often described with parametric models, which affect the predictivity of calculations. In this work, we perform a systematic analysis of LHC measurements from Pb-Pb collisions, by combining an \emph{ab-initio} model of the early stage of the collisions with a hydrodynamic model of the plasma. We obtain state-of-the-art constraints on the shear and bulk viscosity of quark-gluon plasma. We mitigate the additional cost of the ab-initio initial conditions by combining Bayesian model averaging with transfer learning, allowing us to account for important theoretical uncertainties in the hydrodynamics-to-hadron transition. We show that, despite the apparent strong constraints on the shear viscosity, metrics that balance the model's predictivity with its degree of agreement with data do not prefer a temperature-dependent specific shear viscosity over a constant value. We validate the model by comparing with discriminating observables not used in the calibration, finding excellent agreement.

7 pages, 4 figures

References in corpus (15)

• Bayes in the sky: Bayesian inference and model selection in cosmology
• The equation of state in (2+1)-flavor QCD
• Viscosity Information from Relativistic Nuclear Collisions: How Perfect is the Fluid Observed at RHIC?
• Elliptic and triangular flow in event-by-event (3+1)D viscous hydrodynamics
• Alternative ansatz to wounded nucleon and binary collision scaling in high-energy nuclear collisions
• On the Strongly-Interacting Low-Viscosity Matter Created in Relativistic Nuclear Collisions
• Event-by-event gluon multiplicity, energy density and eccentricities at RHIC and LHC
• Transport coefficients for bulk viscous evolution in the relaxation time approximation
• Event-by-event mean $p_{\mathrm{T}}$ fluctuations in pp and Pb-Pb collisions at the LHC
• Quantifying properties of hot and dense QCD matter through systematic model-to-data comparison
• Multi-messenger heavy-ion collision physics
• Constraining the initial state granularity with bulk observables in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV
• Correlations between flow and transverse momentum in Xe+Xe and Pb+Pb collisions at the LHC with the ATLAS detector: a probe of the heavy-ion initial state and nuclear deformation
• Bayesian quantification of strongly-interacting matter with color glass condensate initial conditions
• Efficient emulation of relativistic heavy ion collisions with transfer learning

Cited by in corpus (15)

• Bayesian quantification of strongly-interacting matter with color glass condensate initial conditions
• Bayesian analysis of (3+1)D relativistic nuclear dynamics with the RHIC beam energy scan data
• Recent developments in mathematical aspects of relativistic fluids
• Applications of emulation and Bayesian methods in heavy-ion physics
• Towards constraining QCD phase transitions in neutron star interiors: Bayesian Inference with TOV linear response analysis
• Global Bayesian Analysis of $\mathrm{J}/\psi$ Photoproduction on Proton and Lead Targets
• On model emulation and closure tests for 3+1D relativistic heavy-ion collisions
• Quantification of the low-$p_{\mathrm{T}}$ pion excess in heavy-ion collisions at the LHC and top RHIC energy
• Learning Informed Prior Distributions with Normalizing Flows for Bayesian Analysis
• Phenomenological constraints on QCD transport with quantified theory uncertainties
• Neural network enhanced Bayesian global analysis of relativistic heavy ion collisions
• Mode-by-mode evolution of Pb-Pb collisions at 5.02 TeV in a hybrid model
• Quarkonium in a QCD medium with momentum-dependent relaxation time
• Longitudinal Dynamics of Large and Small Systems from a 3D Bayesian Calibration of RHIC Top-energy Collision Data
• Glauber quark and gluon contributions to quark energy loss at next-to-leading order and next-to-leading twist