Propagation of vector-meson spectral-functions in a BUU type transport model: Application to di-electron production

TL;DR

This paper develops a kinetic theory approach to model the evolution of vector-meson spectral functions within a BUU transport framework, applied to di-electron production in nuclear collisions, highlighting minimal in-medium modifications for small systems.

Contribution

It introduces a formalism for propagating vector-meson spectral functions in a BUU transport model, enabling more accurate simulations of di-electron spectra in nuclear reactions.

Findings

In-medium modifications are small for small collision systems.

The model successfully describes di-electron spectra measured by HADES.

Spectral function evolution is primarily density-driven.

Abstract

The time evolution of vector-meson spectral-functions is studied within a kinetic theory approach. We implement this formalism in a BUU type transport model. Applications focus on rho and omega mesons being important pieces for the interpretation of the di-electron invariant mass spectrum measured by the HADES collaboration for the reaction C + C at 2 AGeV bombarding energy. Since the evolution of the spectral functions is driven by the local density, the in-medium modifications are tiny for small collision systems within this approach.