Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $\eta$-$\gamma$ and $\eta'$-$\gamma$ transition form factors in a
  nonlocal NJL model   We study the $\eta$ and $\eta'$ distribution amplitudes (DAs) in the context
of a nonlocal SU(3)_L x SU(3)_R chiral quark model. The corresponding
Lagrangian allows to reproduce the phenomenological values of pseudoscalar
meson masses and decay constants, as well as the momentum dependence of the
quark propagator arising from lattice calculations. It is found that the
obtained DAs have two symmetric maxima, which arise from new contributions
generated by the nonlocal character of the interactions. These DAs are then
applied to the calculation of the $\eta$-$\gamma$ and $\eta'$-$\gamma$
transition form factors. Implications of our results regarding higher twist
corrections and/or contributions to the transition form factors originated by
gluon-gluon components in the $\eta$ and $\eta'$ mesons are discussed.

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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
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The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex