Quark and Gluon Tomography of the Helium-4 Nucleus.

QCD collinear factorization allows coherent hard exclusive reactions to reveal the quark-gluon structure of light nuclei, enabling their 3D tomography. In this Letter, we investigate elastic form factors and deeply virtual Compton scattering on a helium-4 target. We achieve unprecedented theoretical precision for this type of analysis by constraining generalized parton distributions at next-to-leading order in α_{s}, incorporating kinematic twist corrections, and utilizing full evolution equations. Ultimately, we present the first tomography of a light nucleus, revealing distinct transverse spatial distributions of quarks and gluons.