Tagging the initial-state gluon

TL;DR

This paper develops a theoretically robust method to identify quark-initiated jets in electroweak boson production with jets, enhancing the initial-state gluon contribution to probe proton structure.

Contribution

It introduces a jet tagging technique based on angularity cuts that is infrared and collinear safe, enabling systematic theoretical predictions for transverse momentum distributions.

Findings

The tagging method effectively isolates quark-initiated jets.

Predictions for transverse momentum distributions are systematically improvable.

Enhanced sensitivity to gluonic content in protons is demonstrated.

Abstract

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