# (3+1)-dimensional dissipative relativistic fluid dynamics at non-zero net baryon density

## TL;DR

This paper introduces BEShydro, a (3+1)-dimensional relativistic hydrodynamic code that models high-energy heavy-ion collisions with finite baryon density, including dissipative effects, and provides extensive testing protocols.

## Contribution

The paper presents a new modular (3+1)-D hydrodynamic code for simulating baryon-rich QCD matter with detailed dissipative effects and comprehensive validation tests.

## Key findings

- BEShydro accurately models baryon diffusion and viscous effects.
- The code's modularity allows selective inclusion of physical effects.
- Validation tests demonstrate high precision in baryon transport simulations.

## Abstract

Heavy-ion collisions at center-of-mass energies between 1 and 100 GeV/nucleon are essential to understand the phase diagram of QCD and search for its critical point. At these energies the net baryon density of the system can be high, and simulating its evolution becomes an indispensable part of theoretical modeling. We here present the (3+1)-dimensional diffusive relativistic hydrodynamic code BEShydro which solves the equations of motion of second-order Denicol-Niemi-Molnar-Rischke (DNMR) theory, including bulk and shear viscous currents and baryon diffusion currents. BEShydro features a modular structure that allows to easily turn on and off baryon evolution and different dissipative effects and thus to study their physical effects on the dynamical evolution individually. An extensive set of test protocols for the code, including several novel tests of the precision of baryon transport that can also be used to test other such codes, is documented here and supplied as a permanent part of the code package.