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arXiv · 1612.02445

Gluon orbital angular momentum at small-$x$

Yoshitaka Hatta·Yuya Nakagawa·Bowen Xiao·Feng Yuan·Yong Zhao
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Abstract

We present a general analysis of the orbital angular momentum (OAM) distribution of gluons $L_g(x)$ inside the nucleon with particular emphasis on the small-$x$ region. We derive a novel operator representation of $L_g(x)$ in terms of Wilson lines and argue that it is approximately proportional to the gluon helicity distribution $L_g(x) \approx -2\Delta G(x)$ at small-$x$. We also compute longitudinal single spin asymmetry in exclusive diffractive dijet production in lepton-nucleon scattering in the next-to-eikonal approximation and show that the asymmetry is a direct probe of the gluon helicity/OAM distribution as well as the QCD odderon exchange.

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Yoshitaka Hatta, Yuya Nakagawa, Bowen Xiao, Feng Yuan, Yong Zhao. 2016-12-07. Gluon orbital angular momentum at small-$x$. https://doi.org/10.1103/physrevd.95.114032

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