Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Manifestly Covariant Analysis of the QED Compton Process in $e p\to e
  \gamma p$ and $e p \to e \gamma X$   We calculate the unpolarized QED Compton scattering cross section in a
manifestly covariant way. Our approach allows a direct implementation of the
specific kinematical cuts imposed in the experiments, {\it e. g.} HERA-H1. We
compare the 'exact' cross section in terms of the structure functions $F_{1,2}
(x_B,Q^2)$, assuming the Callan-Gross relation, with the one obtained using the
equivalent photon approximation (EPA) as well as with the experimental results.
We find that the agreement with the EPA is better in $x_{\gamma}$ bins, where
$x_{\gamma}$ is the fraction of the longitudinal momentum of the proton carried
by the virtual photon, compared to the bins in the leptonic variable $x_l$.

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The categories of this paper are: physics
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The categories of this paper are: chem-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-lat
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The categories of this paper are: plasm-ph
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The categories of this paper are: nlin
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The categories of this paper are: cs
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The categories of this paper are: gr-qc
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The categories of this paper are: math
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The categories of this paper are: hep-th
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The categories of this paper are: math-ph
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The categories of this paper are: econ
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The categories of this paper are: solv-int