# SMASH: Results from hadronic transport for heavy-ion collisions at high densities

## TL;DR

This paper reviews the SMASH hadronic transport model, highlighting its software structure, particle production mechanisms, and applications in studying heavy-ion collision observables, fluctuations, electromagnetic probes, and transport coefficients.

## Contribution

It provides a comprehensive overview of SMASH's capabilities, including new methods for cluster production, fluctuation analysis, and integration into hybrid models with Bayesian parameter estimation.

## Key findings

- Constraints on nuclear mean fields from collective flow
- Survival of fluctuations through rescattering stage
- Electromagnetic probes reveal resonance broadening and flow patterns

## Abstract

This mini-review summarizes the general setup and some highlight results from the hadronic transport approach SMASH (Simulating Many Accelerated Strongly-interacting Hadrons). We start by laying out the software development structures as well as the particle properties and how they are determined by elementary collisions. The different ways to produce light clusters in SMASH, either by coalescence or dynamic multi-particle reactions, are explained. The constraints on nuclear mean fields and the corresponding equation of state from collective flow observables are discussed. In addition, we show how fluctuations associated with a potential critical endpoint survive through the hadronic rescattering stage. Besides hadronic observables, electromagnetic probes offer nice possibilities to study the properties of matter. We present results on collisional broadening of resonances and elliptic flow of dileptons. Last but not least, we review how SMASH can be employed as part of a hybrid approach including a Bayesian analysis for transport coefficients as a function of temperature and chemical potential. We end with an outlook how the hybrid approach has been recently extended to lower collision energies by dynamical fluidization initial conditions.