Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Chiral extrapolation of pion-pion scattering phase shifts within
  standard and unitarized Chiral Perturbation Theory   We calculate the pion-pion elastic scattering phase shifts for pion masses
from the chiral limit to values of interest for lattice studies. At low
energies, we use the standard Chiral Perturbation Theory expressions to one and
two loops. In addition, we study the phase shifts mass dependence in the
resonance region by means of dispersion theory in the form of unitarized Chiral
Perturbation Theory and the Inverse Amplitude Method. We pay particular
attention to the case when resonances are close to threshold, illustrating the
different behavior between scalar and vector resonances. We also provide the
estimation of uncertainties, which are dominated by those of the O(p^6) chiral
parameters.

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The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
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The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ