Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The pion form factor at timelike momentum transfers in a dispersion
  approach   We consider a model with $\rho\pi\pi$, $\rho KK$, and gauge-invariant
$\rho\gamma$ couplings and obtain the pion form factor $F_\pi$ at timelike
momentum transfers by resummation of pion and kaon loops. We use a dispersion
representation for the loop diagrams and analyse ambiguities related to
subtraction constants. The resulting representation for $F_\pi$ is shown to
have the form of the conventional vector meson dominance formula with one
important distinction - the effective $\rho$-meson decay constant $f^{\rm
eff}_\rho$ turns out to depend on the momentum transfer. For the
electromagnetic pion form factor we include in addition the $\rho-\omega$
mixing effects. We apply the representations obtained to the analysis of the
data on the pion form factors from $e^+e^-$ annihilation and $\tau$ decay and
extract the $\rho^-$, $\rho^0$ and $\omega$ masses and coupling constants.

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The categories of this paper are: gr-qc
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
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The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
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The categories of this paper are: stat
28
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: solv-int