Heidelberg 2022 – scientific programme

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T: Fachverband Teilchenphysik

T 70: Experimental Methods (general) 3

T 70.8: Talk

Wednesday, March 23, 2022, 18:00–18:15, T-H29

Data-driven corrections to shower shape variables for photon identification at the ATLAS experiment with 13 TeV pp collision data — •Jan Lukas Späh, Björn Wendland, and Johannes Erdmann — Technische Universität Dortmund, Fakultät Physik

Measurements of Standard Model processes, searches for new particles or processes forbidden in the Standard Model with photons in the final state play an important role in the physics programme of the ATLAS experiment. At hadron colliders, studies of photons are particularly challenging, as large background contributions arise from jets that can be misidentified as photons. This requires an identification algorithm that provides high efficiency for genuine photons while ensuring an excellent background rejection for misreconstructed objects.

Currently, this method relies on rectangular cuts on so-called shower shape variables, which capture relevant information about the shape and evolution of the electromagnetic shower and the possible leakage into the hadronic calorimeter. While the longitudal shower development through the calorimeter layers is modelled well, residual mismodelling is observed for lateral shower shape distributions. Therefore, the simulated distributions are corrected with a data-driven approach.

In this talk, studies of univariate first- and second-order corrections obtained from the full Run 2 dataset are discussed and recent improvements are highlighted.