Transport and hydrodynamic calculations of direct photons at FAIR

TL;DR

This paper uses transport and hybrid models to predict direct photon spectra in uranium-uranium collisions at FAIR energies, exploring different equations of state and emission patterns.

Contribution

It introduces a combined transport and hydrodynamic approach to calculate direct photon spectra at FAIR energies, analyzing effects of various equations of state.

Findings

Different equations of state significantly affect photon spectra.

Hybrid model predicts distinct emission patterns in space and time.

Results provide benchmarks for upcoming FAIR measurements.

Abstract

The microscopic transport model UrQMD and a micro+macro hybrid model are used to calculate direct photon spectra from U+U-collisions at Elab = 35 AGeV as will be measured by the CBM-collaboration at FAIR. In the hybrid model, the intermediate high-density part of the nuclear interaction is described with ideal 3+1-dimensional hydrodynamics. Different equations of state of the matter created in the heavy-ion collisions are investigated and the resulting spectra of direct photons are predicted. The emission patterns of direct photons in space and time are discussed.