  We establish the correspondence between two well-known frameworks for QCD
multiple scattering in nuclear media: the Color Glass Condensate (CGC) and the
High-Twist (HT) expansion formalism. We argue that a consistent matching
between both frameworks, in their common domain of validity, is achieved by
incorporating the sub-eikonal longitudinal momentum phase in the CGC formalism,
which mediates the transition between coherent and incoherent scattering. We
perform a detailed calculation and analysis of direct photon production in
proton-nucleus scattering as a concrete example to establish the matching
between HT and CGC up to twist-4, including initial- and final-state
interactions, as well as their interferences. The techniques developed in this
work can be adapted to other processes in electron-nucleus and proton-nucleus
collisions, and they provide a potential avenue for a unified picture of
dilute-dense dynamics in nuclear media.
