Observation of the associated production of a top quark and a Z boson in pp collisions at √s = 13 TeV with the ATLAS detector

Summary, in English

Single top-quark production in association with a Z boson, where the Z boson decays to a pair of charged leptons, is measured in the trilepton channel. The proton-proton collision data collected by the ATLAS experiment from 2015 to 2018 at a centre-of-mass energy of 13 TeV are used, corresponding to an integrated luminosity of 139 fb−1. Events containing three isolated charged leptons (electrons or muons) and two or three jets, one of which is identified as containing a b-hadron, are selected. The main backgrounds are from tt¯ Z and diboson production. Neural networks are used to improve the background rejection and extract the signal. The measured cross-section for tℓ+ℓ−q production, including non-resonant dilepton pairs with mℓ+ℓ−> 30 GeV, is 97 ± 13 (stat.) ± 7 (syst.) fb, consistent with the Standard Model prediction. [Figure not available: see fulltext.] © 2020, The Author(s).

• Author: G Aad; Torsten Åkesson; Simona Bocchetta; Lene Bryngemark; Eric Edward Corrigan; Caterina Doglioni; Jannik Geisen; Kristian Gregersen; Eva Brottmann Hansen; Vincent Hedberg; Göran Jarlskog; Edgar Kellermann; Balazs Konya; Else Lytken; Katja Mankinen; Caterina Marcon; Ulf Mjörnmark; Geoffrey André Adrien Mullier; Ruth Pöttgen; Trine Poulsen; Eleni Skorda; Oxana Smirnova; L Zwalinski
• Department/s: Particle and nuclear physics; eSSENCE: The e-Science Collaboration
• Publishing year: 2020
• Language: English
• Publication/Series: Journal of High Energy Physics
• Volume: 2020
• Issue: 7
• Links: http://dx.doi.org/10.1007/JHEP07(2020)124
• Document type: Journal article
• Publisher: Springer
• Topic: Subatomic Physics
• Keywords: Hadron-Hadron scattering (experiments)
• Status: Published
• ISBN/ISSN/Other: ISSN: 1029-8479