ATLAS - LHC Run 2 jet performance

Jet energy scale systematic uncertainties and jet cleaning for early 2015 data analyses Many searches and measurements using early 2015 data rely on the accurate determination of the jet energy measurement and the rejection of jets arising from non collision backgrounds and detector faults. In this talk, the procedure used to establish the systematic uncertainties on the jet energy scale and resolutions for 2015 data analysis will be described. The uncertainties will be compared to the uncertainties achieved for 2012 data analyses. In addition, variables related to the presence of beam backgrounds and detector imperfections will be shown, comparing them in early data and MC simulations. Based on these studies, selection cuts to reject these backgrounds will be defined and their efficiency to select signal and background jets studied in data. Inputs to jet reconstruction and boosted object tagging with the ATLAS detector at sqrt(s)=13 TeV The LHC has recently concluded a 2-year-long shutdown delivering once more the highest energy proton-proton collisions ever produced in the laboratory. The ATLAS detector has also concluded its upgrades and already collected close to 1 fb-1 of data at the new center of mass energy. In order to be able to understand jet production and boosted object tagging, careful commissioning of the detector and event reconstruction is required. In this talk, efforts made to understand tracks, clusters and jet properties relevant to characterize jet reconstruction will be described. These efforts focus on data/MC comparisons of relevant quantities using this first fb-1. Substructure variables relevant to commissioning the early top and W taggers are also studied, motivating the use of specific variables and tagging cuts for early searches of new particles decaying to boosted tops and Ws in p-p collisions at sqrt(s)=13 TeV.