Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Precision determination of the pi-N scattering lengths and the charged
  pi-NN coupling constant   We critically evaluate the isovector GMO sumrule for the charged $\pi N N$
coupling constant using recent precision data from $\pi ^-$p and $\pi^-$d atoms
and with careful attention to systematic errors. From the $\pi ^-$d scattering
length we deduce the pion-proton scattering lengths ${1/2}(a_{\pi ^-p}+a_{\pi
^-n})=(-20\pm 6$(statistic)$ \pm 10$ (systematic))~$\cdot
10^{-4}m_{\pi_c}^{-1}$ and ${1/2}(a_{\pi ^-p}-a_{\pi ^-n})=(903 \pm 14)\cdot
10^{-4}m_{\pi_c}^{-1}$. From this a direct evaluation gives $g^2_c(GMO)/4\pi
=14.20\pm 0.07$(statistic)$\pm 0.13$(systematic) or $f^2_c/4\pi= 0.0786\pm
0.0008$.

2
The categories of this paper are: math
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
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The categories of this paper are: stat
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The categories of this paper are: nucl-th
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc