Pre-hydrodynamic evolution in large and small systems

Abstract

We extend our previous investigation of the effects of pre-hydrodynamic evolution on final-state observables in heavy-ion collisions to smaller systems. We use a state-of-the-art hybrid model for the numerical simulations with optimal parameters obtained from a previous Bayesian study. By studying p-Pb collisions, we find that the effects due to the assumption of a conformal evolution in the pre-hydrodynamical stage are even more important in small systems. We also show that this effect depends on the time duration of the pre-equilibrium stage, which is further enhanced in small systems. Finally, we show that the recent proposal of a free-streaming with subluminal velocity for the pre-equilibrium stage, thus effectively breaking conformal invariance, can alleviate the contamination of final state observables. Our study further reinforces the need for moving beyond conformal approaches in pre-equilibrium dynamics modeling, especially when extracting transport coefficients from hybrid models in the high-precision era of heavy-ion collisions.

15 pages, 14 figures

References in corpus (12)

• Viscosity in Strongly Interacting Quantum Field Theories from Black Hole Physics
• Glauber Modeling in High Energy Nuclear Collisions
• The equation of state in (2+1)-flavor QCD
• Observation of long-range near-side angular correlations in proton-lead collisions at the LHC
• Alternative ansatz to wounded nucleon and binary collision scaling in high-energy nuclear collisions
• Fully integrated transport approach to heavy ion reactions with an intermediate hydrodynamic stage
• Event-by-event gluon multiplicity, energy density and eccentricities at RHIC and LHC
• Bulk viscosity-driven suppression of shear viscosity effects on the flow harmonics at RHIC
• Causal Viscous Hydrodynamics for Central Heavy-Ion Collisions
• Coupling Relativistic Viscous Hydrodynamics to Boltzmann Descriptions
• Free-streaming approximation in early dynamics of relativistic heavy-ion collisions
• An overview of experimental results from ultra-relativistic heavy-ion collisions at the CERN LHC: bulk properties and dynamical evolution

Cited by in corpus (6)

• Progress and Challenges in Small Systems
• Causality violations in simulations of large and small heavy-ion collisions
• Comparing matching prescriptions between pre-equilibrium and hydrodynamic models in high-energy nuclear collisions
• Universality of scaled particle spectra in ultrarelativistic heavy-ion collisions
• Impact of the pre-equilibrium phase for the determination of nuclear geometry in high-energy isobar collisions
• (3+1)D event-by-event pre-equilibrium dynamics in heavy-ion collisions