Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Recent results from HADES on electron pair production in relativistic
  heavy-ion collisions   Systematic investigations of dilepton production are performed at the SIS
accelerator of GSI with the HADES spectrometer. The goal of this program is a
detailed understanding of di-electron emission from hadronic systems at
moderate temperatures and densities. New results obtained in HADES experiments
focussing on electron pair production in elementary collisions are reported
here. They pave the way to a better understanding of the origin of the
so-called excess pairs earlier on observed in heavy-ion collisions by the DLS
collaboration and lately confirmed in two measurements of the HADES
collaboration using C+C and Ar+KCl collisions. Results of these studies are
discussed.

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The categories of this paper are: physics
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
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The categories of this paper are: cs
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: mtrl-th
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The categories of this paper are: adap-org
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The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: ao-sci