Dortmund 2021 – scientific programme

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T: Fachverband Teilchenphysik

T 53: Electroweak Interactions I

T 53.3: Talk

Wednesday, March 17, 2021, 16:30–16:45, Tc

Estimation of non-prompt lepton background in same-sign WW production at 13 TeV with ATLAS detector — •Shalu Solomon — Albert-Ludwigs University of Freiburg, Freiburg, Germany

The production of same-sign W boson pair via vector boson scattering is one of the pivotal processes to experimentally probe the electroweak symmetry breaking mechanism. The analysis of 2015-2016 ATLAS data at √s = 13 TeV resulted in the observation of the process with the signal significance of 6.5 σ. With the entire Run 2 data set, corresponding to an integrated luminosity of 139 fb⁻¹, the signal event yield has increased approximately by a factor of 4, which gives the potential for the first differential cross-section measurement of this process. The final state consisting of two prompt leptons of the same electric charge, two neutrinos and two forward jets is considered. The second-largest background source, non-prompt lepton background, arises due to leptons from heavy-flavour hadron decays and jets misidentified as electrons, passing the lepton selection criteria. A data-driven technique, called fake factor method, is used to estimate this background. The fake factors are extracted from a jet-enriched sample kinematically close to the signal region. The performance of this background in various validation regions and the estimation in the signal region are presented.