Jet reclustering and close-by effects in ATLAS Run 2

The jet reclustering procedure propagates calibrations and uncertainties from the input jet collections through to the final \largeR jets, exploiting the detailed understanding of the input objects in order to provide greater flexibility at the physics analysis level. The forward-propagation of calibrations and uncertainties to reclustered jets eliminates the need to prepare a specific calibration for each large-R jet collection considered for use in analysis. The performance of reclustered \largeR jets during LHC Run 2 is studied, and compared with that of conventional trimmed \antikt \largeR jets directly constructed from locally-weighted topological clusters. Studies of the modelling of \antikt $R=0.4$ jets in the vicinity of nearby radiation are presented using methods which combine tracking and calorimeter information. Systematic uncertainties resulting from the propagation of the uncertainties on the input jets to the reclustering procedure are studied. Comparisons between 33.2~\ifb~of data collected during 2016 operations and simulation are shown, and the relative jet mass scale and resolution for re-clustered and conventional jets is extracted using the forward-folding technique.