Signature of the Gluon Orbital Angular Momentum

We propose a novel observable for the experimental detection of the gluon orbital angular momentum (OAM) that constitutes the proton spin sum rule. We consider longitudinal double spin asymmetry in exclusive dijet production in electron-proton scattering and demonstrate that the cos 0 azimuthal angle correlation between the scattered electron and proton is a sensitive probe of the gluon OAM at small x and its interplay with the gluon helicity. We also present a numerical estimate of the cross section for the kinematics of the Electron-Ion Collider.

Automated summary

We propose a novel observable to detect the gluon orbital angular momentum (OAM) that constitutes the proton spin sum rule experimentally. We investigate the longitudinal double spin asymmetry in exclusive dijet production in electron-proton scattering and find that the cos 0 azimuthal angle correlation between the scattered electron and proton is a sensitive probe of the gluon OAM at small x and its interplay with the gluon helicity. We also provide a numerical estimate of the cross section for the Electron-Ion Collider kinematics.