Conservation laws in a novel hybrid approach

TL;DR

This paper introduces the SMASH-vHLLE-hybrid model for simulating heavy-ion collisions at high baryon densities, emphasizing the importance of a consistent equation of state for conserving fundamental quantities and accurately predicting observables.

Contribution

The paper presents a novel hybrid model combining SMASH and vHLLE, along with a new hadron resonance gas equation of state, for improved conservation and analysis of heavy-ion collision data.

Findings

The hybrid model conserves energy, baryon number, and electric charge effectively.

The hadron resonance gas equation of state is crucial for model accuracy.

First validation of the model's conservation laws and excitation functions.

Abstract

Heavy-ion collisions covering a wide range of collision energies provide a vast amount of observables characterizing the properties of strongly-interacting matter. In particular collisions towards the high baryon-density regime of the QCD phase-diagram have become of interest to study the postulated first order phase transition and to locate a possible critical end point. In this work, the SMASH-vHLLE-hybrid is presented as a novel hybrid model to theoretically describe such heavy-ion collisions. In addition, the SMASH hadron resonance gas equation of state is introduced. The accuracy of the latter is shown to be of fundamental importance in order to conserve energy, baryon number and electric charge throughout the different stages of the hybrid model. Furthermore, the impact of an inaccurate equation of state on final state observables is discussed. This work constitutes a first validation of the SMASH-vHLLE-hybrid in terms of conservation laws and excitation functions. It is expected to be applied to a broader range of observables in the future.