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arXiv · 1306.4178

Space-time structure of polynomiality and positivity for GPDs

I. V. Anikin·I. O. Cherednikov
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Abstract

We study the space-time structure of polynomiality and positivity---the most important properties which are inherent to the generalized parton distributions (GPDs). In this connection, we re-examine the issue of the time- and normal- ordering in the operator definition of GPDs. We demonstrate that the contribution of the anti-commutator matrix element in the collinear kinematics, which was previously argued to vanish, has to be added in order to satisfy the polynomiality condition. Furthermore, we schematically show that a new contribution due to the anti-commutator modifies likewise the so-called positivity constraint, i.e., the Cauchy-Bunyakovsky-Schwarz inequality, which is another important feature of the GPDs.

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I. V. Anikin, I. O. Cherednikov. 2013-06-18. Space-time structure of polynomiality and positivity for GPDs. https://doi.org/10.1103/physrevd.88.105023

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