Associated jet + electroweak gauge boson production in hadronic collisions at forward rapidities in the color-dipole $S$-matrix framework

Abstract

The cross-section for the associated production of a jet with an electroweak gauge boson ($G = W^{\pm}, Z^0, \gamma$) at forward rapidities in $pp$ and $pA$ collisions is derived within the color - dipole $S$ - matrix framework. We present the full expressions for the differential cross-section of the $q p \rightarrow G q X$ process in the transverse momentum space, considering the longitudinal and transverse polarizations of the gauge boson. We demonstrate that the final formulae can be expressed in terms of the unintegrated gluon distribution and reproduce previous results for the associated jet + $\gamma$ and jet + $Z^0$ production, derived using other frameworks. Moreover, we derive the back - to - back correlation limit of the spectra and show that it can be expressed in terms of the unpolarized and linearly polarized transverse momentum gluon distributions. Our results improve the description of the inclusive jet plus color neutral particle production at forward rapidities, not far from the proton fragmentation region, in $pp$ or $pA$ collisions, and are the main ingredient to study the impact of nonlinear QCD effects in two - particle correlations.