Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Counting Form Factors of Twist-Two Operators   We present a simple method to count the number of hadronic form factors based
on the partial wave formalism and crossing symmetry. In particular, we show
that the number of independent nucleon form factors of spin-n, twist-2
operators (the vector current and energy-momentum tensor being special
examples) is n+1. These generalized form factors define the generalized
(off-forward) parton distributions that have been studied extensively in the
recent literature. In proving this result, we also show how the J^{PC} rules
for onium states arise in the helicity formalism.

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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: astro-ph
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The categories of this paper are: physics
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The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
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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: math
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The categories of this paper are: cmp-lg