Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct photon calculations in heavy-ion collisions at s(NN)**1/2 = 62.4
  - 200 AGeV in a (3+1) dimensional hybrid approach   Direct photon spectra from central Au+Au- and Cu+Cu-collisions at sqrt(s_NN)
= 62.4, 130 and 200 AGeV are calculated within the microscopic transport model
UrQMD and a micro+macro hybrid model. In the latter approach, the high-density
part of the transport evolution is replaced by an ideal 3+1-dimensional
hydrodynamic calculation. We study the impact of viscosity and full local
thermalization and compare the calculations to measurements obtained by the
PHENIX collaboration. We find a reasonable agreement with the experimental data
for calculations involving a Quark-Gluon-Plasma phase.

35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
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The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph