Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Production and constraints for a massive dark photon at
  electron-positron colliders   Dark sector may couple to the Standard Model via one or more mediator
particles. We discuss two types of mediators: the dark photon $A^{\prime}$ and
the dark scalar mediator $\phi$. The total cross-sections and various
differential distributions of the processes $e^{+} e^{-} \rightarrow q \bar{q}
A^{\prime}$ and $e^{+} e^{-} \rightarrow q \bar{q} \phi$ ($q=u,~d,~c,~s$ and
$b$ quarks) are discussed. We focus on the study of the invisible $A^{\prime}$
due to the cleaner background at future $e^{+} e^{-}$ colliders. It is found
that the kinematic distributions of the two-jet system could be used to
identify (or exclude) the dark photon and the dark scalar mediator, as well as
to distinguish between them. We further study the possibility of a search for
dark photons at a future CEPC experiment with $\sqrt{s}=$ 91.2 GeV and 240 GeV.
With CEPC running at $\sqrt{s}=$ 91.2 GeV, it would be possible to perform a
decisive measurement of the dark photon (20 GeV $< m_{A^{\prime}} <$ 60 GeV) in
less than one operating year. The lower limits of the integrated luminosity for
the significance $S/\sqrt{B}=$ 2$\sigma$, 3$\sigma$ and 5$\sigma$ are
presented.

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The categories of this paper are: hep-th
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: eess
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci