Karlsruhe 2024 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 62: Standard model 2 (electroweak/bosons)

T 62.4: Vortrag

Mittwoch, 6. März 2024, 16:45–17:00, Geb. 30.23: 2/0

Measurement of ZZγ final states with the ATLAS detector at the LHC — •Anke Ackermann — Kirchhoff-Institute for Physics, Heidelberg University

The Standard Model of Particle Physics (SM) predicts the rare production of triboson final states. Although suffering from small cross sections and hence a limited amount of signal events, such triboson states can be studied with the vast amount of data collected by the ATLAS detector in Run 2. In addition to validating the predictions of the SM for rare processes, sensitivity to New Physics is given via anomalous quartic couplings of e.g. four neutral gauge bosons. This talk will focus on the analysis of the simultaneous production of ZZγ. In order to determine the cross sections of this process, it is crucial to separate signal events from events arising through background processes mimicking the signal topology. The most dominant background process contains fake photons, which are non-prompt photons within jets. Due to the limited statistics a new approach with jet ratios is applied to estimate the amount of fake photons in the signal region. Additionally, processes with misidentified leptons contribute to the background. Their contribution is estimated with the likelihood matrix method. After giving a general introduction about the triboson production of the ZZγ process, a summary of the analysis, including the event selection and the background estimation, is presented.

Keywords: elektroweak physics; ATLAS; Z boson; triboson