Dilepton Production in Transport Calculations and Coarse-Grained Dynamics

FAIR NExt generation of ScientistS 2013

Endres, Stephan^1,2 ; Van Hees, Hendrik^1,2 ; Weil, Janus^2 ; Bleicher, Marcus^1,2

Institut für Theoretische Physik, Universität Frankfurt, Max-von-Laue-Straße 1, 60438 Frankfurt, Germany^1

Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt, Germany^2

关键词: Coarse grained dynamics;    Dilepton production;    Elementary reaction;    Heavy ion collision;    Invariant-mass spectra;    Relativistic quantum molecular dynamics;    Transport calculation;    Transport modeling;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/503/1/012039/pdf
DOI  :  10.1088/1742-6596/503/1/012039

来源: IOP

【 摘 要 】

We present transport calculations with the Ultra-relativistic Quantum Molecular Dynamics approach (UrQMD) for dilepton spectra at SIS energies and simulations for NA60 within a coarse-graining approach. While the transport model obtains a good agreement with experiment for elementary reactions, in heavy-ion collisions an excess in the invariant mass spectra is observed which cannot be described by the model. As the pure transport calculations do not include explicit in-medium effects and are limited to hadronic degrees of freedom, we present an alternative approach that uses coarse-grained output from transport calculations to determine thermal dilepton emission rates. For this we apply the medium-modified ρ spectral function by Eletsky et al. In a first exemplary comparison to data from the NA60 experiment we find that the coarse-graining approach gives reasonable results.