Gluon TMDs from Forward $pA$ Collisions in the CGC

We calculate the production of a photon and two jets at forward rapidity in proton–nucleus collisions within the hybrid dilute-dense framework in the Color Glass Condensate (CGC) formalism. After obtaining the cross section for the quark-initiated channel, we consider the correlation limit, in which the vector sum of the transverse momenta of the three outgoing particles is small with respect to the individual transverse momenta. In this limit, the cross section simplifies considerably and can be written in a factorized form, sensitive to various unpolarized and linearly-polarized transverse-momentum-dependent gluon distribution functions (gluon TMDs).