Momentum Imbalance Observables as a Probe of Gluon TMDs

TL;DR

This paper proposes using momentum imbalance observables in heavy quark, jet pair, Higgs, and quarkonium production to probe gluon transverse momentum dependent distributions (TMDs) in unpolarized collisions, providing a new method to study gluon structure.

Contribution

It introduces analytical expressions for momentum imbalance observables sensitive to gluon TMDs and discusses their potential measurements at future EIC and LHC experiments.

Findings

Analytical formulas for gluon TMD-sensitive observables.

Potential to extract gluon TMD size and shape.

Insights into process and energy scale dependence of gluon TMDs.

Abstract

The unpolarized and linearly polarized gluon TMDs can be directly probed in heavy quark and jet pair production in unpolarized electron-proton collisions by looking at observables, like transverse momentum distributions and azimuthal asymmetries, depending on the momentum imbalance of the pair. Analytical expressions are presented for these observables and for analogous ones in Higgs plus jet and quarkonium plus photon production in unpolarized proton-proton scattering experiments. It is shown how the proposed measurements, to be performed at a future EIC and at the LHC, could provide important information on the size and shape of gluon TMDs, as well as on other fundamental properties such as their process and energy scale dependences.