Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Does confinement imply CP invariance of the strong interactions?   The strong coupling constant $1/g^2$ and the vacuum angle $\theta$ of the
SU(3) Yang-Mills theory are investigated in the infrared limit under the
renormalization group flow. It is shown that the theory has an infrared
attractive fixed point at $1/g^2 = \theta = \,0$, which leads to linear
confinement and naturally solves the strong CP problem. In particular, any
initial value of $\theta \neq 0$ is found to be driven to $\theta = 0$ at
macroscopic distances, where quarks and gluons freeze into hadrons by the
confinement mechanism.

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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: econ
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The categories of this paper are: supr-con
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The categories of this paper are: funct-an
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The categories of this paper are: physics
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The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th