ATLAS QCD Jet Measurements

This article presents a recent QCD measurement of the jet cross-section ratios from the ATLAS experiment at CERN’s Large Hadron Collider, using proton–proton collisions at a center-of-mass energy of 13 TeV. The jet cross-section ratios are derived from multi-differential particle-level cross sections for several inclusive jet multiplicity bins for at least 2, 3, 4, and 5 jets. These ratios improve sensitivity to the strong coupling parameter while reduce sensitivity to uncorrelated systematic uncertainties and parton distribution functions. The three-to-two jet cross-section ratio is reported for the first time at 13 TeV center-of-mass energy. Additionally, higher jet multiplicity ratios are measured experimentally for the first time, providing a crucial reference for future theoretical developments in high-precision QCD predictions involving multiple jets. Abstract Published by the Jagiellonian University 2025 authors