Gluon imaging using azimuthal correlations in diffractive scattering at\n the Electron-Ion Collider

Abstract

We study coherent diffractive photon and vector meson production in\nelectron-proton and electron-nucleus collisions within the Color Glass\nCondensate effective field theory. We show that electron-photon and\nelectron-vector meson azimuthal angle correlations are sensitive to non-trivial\nspatial correlations in the gluon distribution of the target, and perform\nexplicit calculations using spatially dependent McLerran-Venugopalan initial\ncolor charge configurations coupled to the numerical solution of small $x$\nJIMWLK evolution equations. We compute the cross-section differentially in\n$Q^2$ and $|t|$ and find sizeable anisotropies in the electron-photon and\nelectron-$\\mathrm{J}/\\psi$ azimuthal correlations ($v_{1,2} \\approx 2 - 10 \\%$)\nin electron-proton collisions for the kinematics of the future Electron-Ion\nCollider. In electron-gold collisions these modulations are found to be\nsignificantly smaller ($v_{1,2} <0.1 \\%$). We also compute incoherent\ndiffractive production where we find that the azimuthal correlations are\nsensitive to fluctuations of the gluon distribution in the target.\n