Spin structure of the pion.
We present the first calculation of the transverse spin structure of the pion in lattice QCD. Our simulations are based on two flavors of nonperturbatively improved Wilson fermions, with pion masses as low as 400 MeV in volumes up to (2.1 fm)(3) and lattice spacings below 0.1 fm. We find a characteristic asymmetry in the spatial distribution of transversely polarized quarks. This asymmetry is very similar in magnitude to the analogous asymmetry we previously obtained for quarks in the nucleon. Our results support the hypothesis that all Boer-Mulders functions are alike.
Deutsches Elektronen-Synchrotron DESY, 22603 Hamburg, Germany.
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D
Brömmel
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M
Diehl
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M
Göckeler
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P
Hägler
R
R
Horsley
Y
Y
Nakamura
D
D
Pleiter
P E L
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Rakow
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A
Schäfer
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G
Schierholz
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Stüben
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Zanotti