TY - JOUR

T1 - Combination of searches for singly produced vectorlike top quarks in 𝑝⁢𝑝 collisions at √𝑠 =13  TeV with the ATLAS detector

AU - The ATLAS collaboration

AU - Ali, Hanadi

AU - Alsolami, Zainab

AU - Barton, A.E.

AU - Borissov, G.

AU - Bouhova-Thacker, E.V.

AU - Ferguson, Ruby

AU - Ferrando, James

AU - Fox, H.

AU - Hagan, Alina

AU - Henderson, R.C.W.

AU - Jones, R.W.L.

AU - Kartvelishvili, V.

AU - Love, P.A.

AU - Marshall, E.J.

AU - Meng, L.

AU - Muenstermann, D.

AU - Sampson, Elliot

AU - Smizanska, M.

AU - Wharton, A.M.

PY - 2025/1/29

Y1 - 2025/1/29

N2 - A combination of searches for the single production of vectorlike top quarks (𝑇) is presented. These analyses are based on proton-proton collisions at √𝑠 =13  TeV recorded in 2015–2018 with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. The 𝑇 decay modes considered in this combination are into a top quark and either a Standard Model Higgs boson or a 𝑍 boson (𝑇 →𝐻⁡𝑡 and 𝑇→𝑍⁢𝑡). The individual searches used in the combination are differentiated by the number of leptons (𝑒, 𝜇) in the final state. The observed data are found to be in good agreement with the Standard Model background prediction. Interpretations are provided for a range of masses and couplings of the vectorlike top quark for benchmark models and generalized representations in terms of 95% confidence level limits. For a benchmark signal prediction of a vectorlike top quark SU(2) singlet with electroweak coupling, 𝜅, of 0.5, masses below 2.1 TeV are excluded, resulting in the most restrictive limits to date.

AB - A combination of searches for the single production of vectorlike top quarks (𝑇) is presented. These analyses are based on proton-proton collisions at √𝑠 =13  TeV recorded in 2015–2018 with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. The 𝑇 decay modes considered in this combination are into a top quark and either a Standard Model Higgs boson or a 𝑍 boson (𝑇 →𝐻⁡𝑡 and 𝑇→𝑍⁢𝑡). The individual searches used in the combination are differentiated by the number of leptons (𝑒, 𝜇) in the final state. The observed data are found to be in good agreement with the Standard Model background prediction. Interpretations are provided for a range of masses and couplings of the vectorlike top quark for benchmark models and generalized representations in terms of 95% confidence level limits. For a benchmark signal prediction of a vectorlike top quark SU(2) singlet with electroweak coupling, 𝜅, of 0.5, masses below 2.1 TeV are excluded, resulting in the most restrictive limits to date.

U2 - 10.1103/physrevd.111.012012

DO - 10.1103/physrevd.111.012012

M3 - Journal article

VL - 111

JO - Physical Review D

JF - Physical Review D

SN - 2470-0010

IS - 1

M1 - 012012

ER -