Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Contribution of \sigma-meson exchange to elastic lepton-proton
  scattering   Lepton mass effects play a decisive role in description of elastic
lepton-proton scattering when the beam's energy is comparable to the mass of
the lepton. The future MUSE experiment, which is devised to solve the "Proton
Radius Puzzle", is going to cover the corresponding kinematic region for a
scattering of muons by a proton target. We anticipate that helicity-flip meson
exchanges will make a difference in comparison of elastic electron-proton
versus muon-proton scattering in MUSE. In this article, we estimate the
$\sigma$ meson exchange contribution in the $t$-channel. This contribution,
mediated by two-photon coupling of $\sigma$, is calculated to be at most $\sim
0.1 \%$ for muons in the kinematics of MUSE and it is about 3 orders in
magnitude larger than for electrons because of the lepton-mass difference.

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The categories of this paper are: hep-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
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The categories of this paper are: bayes-an
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The categories of this paper are: cs
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The categories of this paper are: acc-phys