ATLAS jet energy scale and resolution in early Run 2

Jet energy scale measurements and their systematic uncertainties are reported for jets measured with the ATLAS detector using proton-proton collision data with a center-of-mass energy of ffiffi s p ¼ 13 TeV, corresponding to an integrated luminosity of 3.2 fb−1 collected during 2015 at the LHC. Jets are reconstructed from energy deposits forming topological clusters of calorimeter cells, using the anti-kt
\nalgorithm with radius parameter R ¼ 0.4. Jets are calibrated with a series of simulation-based corrections and in situ techniques. In situ techniques exploit the transverse momentum balance between a jet and a reference object such as a photon, Z boson, or multijet system for jets with 20 < pT < 2000 GeV and pseudorapidities of jηj < 4.5, using both data and simulation. An uncertainty in the jet energy scale of less than 1% is found in the central calorimeter region (jηj < 1.2) for jets with 100 < pT < 500 GeV. An uncertainty of about 4.5% is found for low-pT jets with pT ¼ 20 GeV in the central region, dominated by uncertainties in the corrections
\nfor multiple proton-proton interactions. The calibration of forward jets (jηj > 0.8) is derived from dijet pT balance measurements. For jets of pT ¼ 80 GeV, the additional uncertainty for the forward jet calibration reaches its largest value of about 2% in the range jηj > 3.5 and in a narrow slice of 2.2 < jηj < 2.4.