# A hybrid approach to relativistic heavy-ion collisions at the RHIC BES energies

## TL;DR

This paper develops a comprehensive (3+1)D hybrid model combining viscous hydrodynamics and hadronic cascade to study relativistic heavy-ion collisions at RHIC BES energies, emphasizing baryon diffusion and pre-equilibrium effects.

## Contribution

It introduces a full (3+1)D hybrid framework including baryon diffusion and a dynamical initialization scheme for RHIC BES collisions, addressing effects previously unmodeled.

## Key findings

- Quantitative impact of net-baryon diffusion on observables
- Study of longitudinal structure and fluctuations in collisions
- Assessment of pre-equilibrium stage importance

## Abstract

Using a hybrid (viscous hydrodynamics + hadronic cascade) framework, we model the bulk dynamical evolution of relativistic heavy-ion collisions at Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan (BES) collision energies, including the effects from non-zero net baryon current and its dissipative diffusion. This framework is in full (3+1)D, which allows us to study the non-trivial longitudinal structure and dynamics of the collision systems, for example baryon stopping and transport, as well as longitudinal fluctuations. For the first time, the quantitative effect of net-baryon diffusion on hadronic observables is addressed. Finally, we propose a dynamical initialization scheme to study the importance of the pre-equilibrium stage at the RHIC BES energies.