Precision Jet Substructure Measurements with ATLAS Run 2 Data

Theoretical calculations for jet substructure observables with accuracy beyond leading-logarithm have recently become available. Such well-understood observables provide novel probes of QCD in a new, collinear regime at the LHC. This talk presents new measurements of jet substructure observables by the ATLAS collaboration using Run 2 LHC data. These measurements are unfolded to particle-level to make comparisons with Monte Carlo simulations and state-of-the-art analytical calculations.