Tagging the initial-state gluon

Abstract We study the production of an electroweak boson in association with jets, processes where jet highest transverse momentum is identified as quark-initiated. The quark/gluon tagging procedure realised by a cut on angularity and it therefore theoretically well-defined exhibits infrared collinear safety. In this context, exploiting resummed perturbation theory, we are able to provide theoretical predictions for distributions at and, principle, systematically improvable accuracy. particular, leading quark-initiated allows us enhance initial-state gluon contribution. Thus these novel potentially interesting observables probe gluonic degrees freedom colliding protons.