Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electromagnetic and Scalar Pion form factor in the Kroll-Lee-Zumino
  model   The renormalizable Abelian quantum field theory model of Kroll, Lee, and
Zumino is used at the one loop level to compute vertex corrections to the
tree-level, Vector Meson Dominance (VMD) electromagnetic pion form factor.
These corrections, together with the one-loop vacuum polarization contribution,
imply a resulting electromagnetic pion form factor in excellent agreement with
data in the whole range of accessible momentum transfers in the space-like
region. The time-like form factor, which reproduces the Gounaris-Sakurai
formula at and near the rho-meson peak, is unaffected by the vertex correction
at order $\cal{O}$$(g^2)$. The KLZ model is also used to compute the scalar
radius of the pion at the one loop level, finding $<r^{2}_{\pi}>_{S} = 0.40
fm^{2}$. This value implies for the low energy constant of chiral perturbation
theory $\bar{l}_{4} =3.4$.

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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
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The categories of this paper are: q-bio
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The categories of this paper are: hep-th
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: quant-ph
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The categories of this paper are: math