https://doi.org/10.1140/epjc/s10052-009-0987-1
Regular Article - Theoretical Physics
Direct photon emission from hadronic sources: hydrodynamics vs. transport theory
1
Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, 60438, Frankfurt am Main, Germany
2
Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität, Max-von-Laue-Str. 1, 60438, Frankfurt am Main, Germany
* e-mail: baeuchle@th.physik.uni-frankfurt.de
Received:
2
October
2008
Revised:
4
February
2009
Published online:
8
April
2009
Direct photon emission in heavy-ion collisions is calculated within the relativistic microscopic transport model UrQMD. We compare the results from the pure transport calculation to a hybrid-model calculation, where the high-density part of the evolution is replaced by an ideal 3-dimensional fluid-dynamic calculation. The effects of viscosity, present in the transport model but neglected in ideal fluid dynamics, are examined. We study the contribution of different production channels and non-thermal collisions to the spectrum of direct photons. Detailed comparisons to the measurements by the WA 98 collaboration are undertaken.
© Springer-Verlag , 2009
