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On the validity of Lorentz invariance relations between parton distributions

M. Schlegel·A. Metz
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Abstract

Lorentz invariance relations connecting twist-3 parton distributions with transverse momentum dependent twist-2 distributions have been proposed previously. These relations can be extracted from a covariant decomposition of the quark-quark correlator. It is argued, however, that the derivation of the Lorentz invariance relations fails if the path-ordered exponential is taken into account in the correlator. The model independent analysis is supplemented by an explicit calculation of the corresponding parton distributions in perturbative QCD with a quark target, and in a simple spectator model. We also clarify the status of a specific calculation of time-reversal even parton distributions in light-cone gauge.

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M. Schlegel, A. Metz. 2004-06-25. On the validity of Lorentz invariance relations between parton distributions. https://arxiv.org/abs/hep-ph/0406289

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