Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light scalars coupled to photons and non-newtonian forces   A particle $\phi$ coupling to two photons couples also to charged particles,
like protons, through a loop. If the particle is a light scalar this induced
coupling to protons leads to non-newtonian forces. We show that the
experimental constraints on exotic, fifth-type forces lead to stringent
constraints on the $\phi\gamma\gamma$ coupling.

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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: atom-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: physics
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The categories of this paper are: math
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The categories of this paper are: chem-ph
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn