Karlsruhe 2024 – scientific programme

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T: Fachverband Teilchenphysik

T 55: Methods in particle physics 4 (HCAL, jets)

T 55.4: Talk

Wednesday, March 6, 2024, 16:45–17:00, Geb. 20.30: 2.066

In Situ Calibration of Large-Radius Jets Using the Direct Balance Method with Z+jets Events in ATLAS — •Donna Maria Mattern and Chris Malena Delitzsch — TU Dortmund, Fakultät Physik

The calibration of the jet energy scale (JES) is a critical step in the preparation of jets that are utilized in precision measurements, as well as searches for physics beyond the Standard Model. Large-radius (R = 1.0) jets are reconstructed from unified flow objects which combine calorimeter signals with charged-particle tracks in the inner detector of the ATLAS detector to achieve optimal performance across a wide kinematic range. They are groomed in order to remove contributions from pile-up. After a Monte Carlo (MC) based calibration to the energy and mass scale of particle-level jets, an in situ calibration of the JES is performed to remove residual differences between data and MC simulated samples due to passive detector material, effects of the jet reconstruction algorithm, fragmentation, or pile-up. Different methods are combined to provide a calibration over a wide kinematic range. The direct balance method using Z+jets events, where the Z-boson decays into charged-lepton pairs, uses a selection with a back-to-back topology of the large-radius jets and the Z-bosons. Scale factors are derived to calibrate the large-radius jet’s transverse momentum to the one of the well-calibrated reference object given by the reconstructed Z-boson. Data collected by the ATLAS detector in proton-proton collisions of LHC-Run 2, and corresponding MC simulated samples are used for the studies.

Keywords: Calibration; in situ; Large-Radius Jets; Direct Balance Method; Z+jets events