Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Long Distance Contribution to $K^+ \rightarrow \pi^+ \nu \bar\nu$   We estimate the long distance contribution to the $K^+ \rightarrow \pi^+ \nu
\bar\nu$ decay amplitude using chiral perturbation theory. We find that it is
likely to be less than a few percent of the part of the short distance
contribution proportional to the square of the charm quark mass. In the large
$N_c$ limit the leading (in chiral perturbation theory) long distance
contribution to $K^+ \rightarrow \pi^+ \nu \bar\nu$ from Feynman diagrams with
a $W$ and $Z^0$ vanishes.

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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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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: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: physics
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The categories of this paper are: bayes-an
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-th