Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Connected and disconnected quark contributions to hadron spin   By introducing an external spin operator to the fermion action, the quark
spin fractions of hadrons are determined from the linear response of the hadron
energies using the Feynman-Hellmann (FH) theorem. At our SU(3)-flavour
symmetric point, we find that the connected quark spin fractions are
universally in the range 55-70\% for vector mesons and octet and decuplet
baryons. There is an indication that the amount of spin suppression is quite
sensitive to the strength of SU(3) breaking. We also present first preliminary
results applying the FH technique to calculations of quark-line disconnected
contributions to hadronic matrix elements of axial and tensor operators. At the
SU(3)-flavour symmetric point we find a small negative contribution to the
nucleon spin from disconnected quark diagrams, while the corresponding tensor
matrix elements are consistent with zero.

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The categories of this paper are: math
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The categories of this paper are: chem-ph
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The categories of this paper are: physics
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The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-ex
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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: patt-sol
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The categories of this paper are: astro-ph
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph