Low mass lepton pair production in hadron collisions

TL;DR

This paper shows that low mass lepton pair production in hadron collisions, dominated by quark-gluon scattering at high transverse momentum, provides a clean way to probe the gluon density in protons, reducing uncertainties compared to prompt photon methods.

Contribution

It demonstrates that lepton pair production can effectively probe gluon density, similar to prompt photon production, but with fewer theoretical and experimental uncertainties.

Findings

Lepton pair production is dominated by quark-gluon scattering at high transverse momentum.

It offers a sensitive probe of gluon density in hadrons.

Reduces uncertainties compared to prompt photon production.

Abstract

The hadroproduction of lepton pairs with mass $Q$ and transverse momentum $Q_T$ can be described in perturbative QCD by the same partonic subprocesses as prompt photon production. We demonstrate that, like prompt photon production, lepton pair production is dominated by quark-gluon scattering in the region $Q_T>Q/2$. This leads to sensitivity to the gluon density in kinematical regimes that are accessible both at collider and fixed target experiments while eliminating the theoretical and experimental uncertainties present in prompt photon production.