LAUSR

Author(s): Hatta, Y; Nakagawa, Y; Xiao, B; Yuan, F; Zhao, Y | Abstract: © 2017 American Physical Society. We present a general analysis of the orbital angular momentum (OAM) distribution of gluons Lg(x) inside the nucleon with particular emphasis on the small-x region. We derive a novel operator representation of Lg(x) in terms of Wilson lines and argue that it is approximately proportional to the gluon helicity distribution Lg(x)≈-2ΔG(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.