Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cornering the axion with CP-violating interactions   Besides CP-preserving interactions, axions and axion-like particles may also
have small CP-violating scalar Yukawa interactions with nucleons and electrons.
Any such interaction will generate macroscopic monopole-dipole forces which can
be searched for experimentally. When the best experimental limits on scalar
interactions are combined with stellar energy-loss arguments constraining
pseudoscalar interactions, strong bounds can be set on CP-violating axion
couplings which almost intersect the expectation for QCD models. Over the
years, both astrophysical and laboratory tests have improved. We provide a
much-needed up-to-date compilation of these constraints, showing improvements
in some regions of parameter space by factors between 40 and 130. We advocate
experimental opportunities, without astrophysical or dark-matter assumptions,
to track down the axion in the lesser-explored corners of its parameter space.

10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
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The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math