Comparing matching prescriptions between pre-equilibrium and hydrodynamic models in high-energy nuclear collisions

Journal Article · 29 October 2024 · European Physical Journal. C, Particles and Fields (Online)

DOI: https://doi.org/10.1140/epjc/s10052-024-13509-8 · OSTI ID:2479406

Borghini, Nicolas ; Krupczak, Renata ; Roch, Hendrik

Abstract State-of-the-art simulations of high-energy nuclear collisions rely on hybrid setups, involving in particular a pre-equilibrium stage to let the system evolve from a far-from-equilibrium initial condition towards a near-equilibrated state after which fluid dynamics can be applied meaningfully. A known issue is the mismatch between the equation of state in the fluid-dynamical evolution and the effective one in the previous stage, which leads to discontinuities at the interface between the two models. Here we introduce a new matching prescription at this interface, based on the entropy, and we compare it with the standard one relying on local energy conservation. We study the behavior of various quantities at the switching time between the models and investigate a number of final-state hadronic observables. For the latter, we show that they are not modified significantly by the choice of matching prescription, provided an appropriate normalization is chosen for the initial state. In turn, our approach reduces sizeably the ratio of bulk over thermodynamic pressure at the beginning of the fluid-dynamical stage.

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0024232
• OSTI ID: 2479406
• Journal Information: European Physical Journal. C, Particles and Fields (Online), Journal Name: European Physical Journal. C, Particles and Fields (Online) Journal Issue: 10 Vol. 84; ISSN 1434-6052
• Publisher: Springer Science + Business MediaCopyright Statement
• Country of Publication: Germany
• Language: English