Search for dark matter produced in association with a single top quark in $$\sqrt{s}=13$$ TeV $$pp$$ collisions with the ATLAS detector

Journal article

Abstract This paper presents a search for dark matter in the context of a two-Higgs-doublet model together with an additional pseudoscalar mediator, a , which decays into the dark-matter particles. Processes where the pseudoscalar mediator is produced in association with a single top quark in the 2HDM+ a model are explored for the first time at the LHC. Several final states which include either one or two charged leptons (electrons or muons) and a significant amount of missing transverse momentum are considered. The analysis is based on proton–proton collision data collected with the ATLAS experiment at $$\sqrt{s} = 13$$ s = 13 TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 $$\hbox {fb}^{-1}$$ fb - 1 . No significant excess above the Standard Model predictions is found. The results are expressed as 95% confidence-level limits on the parameters of the signal models considered.

Authors: Aad, G; Abbott, B; Abbott, DC; Abud, AA; Abeling, K

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: SpringerOpen
• Journal: The European Physical Journal C
• Volume: 81
• Issue: 10
• Pages: 860
• Article number: 860
• Publication date: 2021-10-01
• DOI: 10.1140/epjc/s10052-021-09566-y
• EISSN: 1434-6052
• ISSN: 1434-6044
• Language: English
• Keywords: Quark; Standard Model (mathematical formulation); Top quark; Pseudoscalar; Physics; Particle physics; Atlas (anatomy); Muon; Large Hadron Collider; ATLAS experiment; Lepton; Higgs boson; Electron; Dark matter; Nuclear physics