Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constraints on Scalar Couplings from $\pi^\pm \to l^\pm\nu_l$   New interactions with Lorentz scalar structure, arising from physics beyond
the standard model of electroweak interactions, will induce effective
pseudoscalar interactions after renormalization by weak interaction loop
corrections. Such induced pseudoscalar interactions are strongly constrained by
data on $\pi^\pm \to l^\pm \nu_l$ decay. These limits on induced pseudoscalar
interactions imply limits on the underlying fundamental scalar interactions
that in many cases are substantially stronger than limits on scalar
interactions from direct Beta-decay searches.

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The categories of this paper are: nlin
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The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
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The categories of this paper are: nucl-th
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The categories of this paper are: cs
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The categories of this paper are: solv-int
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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: astro-ph
21
The categories of this paper are: adap-org
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: physics
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The categories of this paper are: math-ph