Göttingen 2025 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 83: Methods in Particle Physics IV (Lepton Reconstruction)

T 83.1: Vortrag

Donnerstag, 3. April 2025, 16:15–16:30, VG 4.101

Electron Reconstruction Efficiencies in Run 2 and Run 3 at ATLAS — •Marius Melcher, Asma Hadef, and Arno Straessner — Technische Universität Dresden

Before particles detected by the ATLAS experiment can be used in physics analyses, their measured signatures undergo several analysis steps, e.g. reconstruction and identification. It is crucial that these steps and their performances are well understood. This talk will focus on the electron reconstruction and the measurement of its efficiency.

For electron reconstruction, information from different parts of the detector needs to be connected: a track from the Inner Detector is matched to energy deposits in the EM calorimeter by reconstruction algorithms. To estimate how many real electrons successfully pass these algorithms the tag-and-probe method is used for Z → ee decays to measure efficiencies both for data and Monte Carlo simulation in dependence of p_T and η. These results are then used to derive scale factors which are applied to correct MC predictions in subsequent analyses with electrons in the final state. In addition to the scale factors also their uncertainty is passed to the analyses. Understanding and controlling the systematic uncertainties of the efficiency measurement is therefore crucial.

After introducing the method and its data-driven approach for background estimation, recent results for the full Run 2 and already available Run 3 datasets are discussed.

Keywords: ATLAS; Reconstruction; Tag-and-Probe; Performance Studies; EGamma