Precision measurements of jet and photon production at ATLAS

TL;DR

This paper presents recent ATLAS measurements of jet and photon production at the LHC, testing perturbative QCD predictions, probing proton structure, and exploring new event-shape observables with implications for fundamental physics.

Contribution

It reports new experimental results on photon and jet production, including measurements sensitive to gluon PDFs, strong coupling, and novel event-shape variables, compared to advanced theoretical predictions.

Findings

Photon production ratios constrain gluon PDFs.

Jet energy flow variables inform strong coupling constant.

New event-shape observables using energy mover's distance.

Abstract

The production of jets and prompt isolated photons at hadron colliders provides stringent tests of perturbative QCD. The latest measurements performed by the ATLAS Collaboration at the LHC are presented in these proceedings. The inclusive prompt-photon production is measured for two distinct photon isolation cones, $R = 0.2$ and $0.4$, as well as for their ratio. This measurement is sensitive to the gluon parton density distribution in the proton. In addition, a measurement of variables probing the properties of the multijet energy flow which are used to determine the strong coupling constant is presented. These measurements are compared to state-of-the-art NLO and NNLO predictions. Lastly, a measurement of new event-shape jet observables defined in terms of reference geometries with cylindrical and circular symmetries using the energy mover's distance is discussed.