Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pion form factor from a contact interaction   In a Poincare'-covariant vector-boson-exchange theory, the pion possesses
components of pseudovector origin, which materially influence its observable
properties. For a range of such quantities, we explore the consequences of a
momentum-independent interaction, regularised in a symmetry-preserving manner.
The contact interaction, whilst capable of describing pion static properties,
produces a form factor whose: evolution for Q^2>0.17GeV^2 disagrees markedly
with experiment; and asymptotic power-law behaviour conflicts strongly with
perturbative-QCD.

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The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: q-alg
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The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg
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The categories of this paper are: astro-ph
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: hep-ex
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The categories of this paper are: cs
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The categories of this paper are: quant-ph
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The categories of this paper are: cond-mat