Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase Motion of the Scalar $\pi \pi$ Amplitudes in $D^+$, $D^+_s \to
  \pi^-\pi^+\pi^+$ Decays   We make a direct and model-independent measurement of the low $\pi^+\pi^-$
mass phase motion in the $D^+ \to \pi^-\pi^+\pi^+$ decay. Our preliminary
results show a strong phase variation, compatible with the isoscalar
$\sigma(500)$ meson. This result confirms our previous result where we found
evidence for the existence of this scalar particle using full Dalitz-plot
analysis. We apply the Amplitude Difference (AD) method to the same Fermilab
E791 data sample used in the preceding analysis. We also give an example of how
we extract the phase motion of the scalar amplitude, looking at the $f_0(980)$
in $D^+_s \to \pi^-\pi^+\pi^+$ decay.

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The categories of this paper are: plasm-ph
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The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: stat
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The categories of this paper are: nucl-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: math
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The categories of this paper are: mtrl-th