Aad, G.Aakvaag, E.Abbott, B.Abdelhameed, S.Abeling, K.Abicht, N.J.Abidi, S.H.Aboelela, M.Aboulhorma, A.Abramowicz, H.Abreu, H.Abulaiti, Y.Acharya, B.S.Ackermann, A.Adam Bourdarios, C.Adamczyk, L.Addepalli, S.V.Addison, M.J.Adelman, J.Adiguzel, A.et al.2025-05-082025-05-082025Journal of High Energy Physics (JHEP), 2025; 2025(2):84-0-84-511029-84791029-8479https://hdl.handle.net/2440/144433Published: February 12, 2025A search for the production of top-quark pairs with the same electric charge (tt or ¯t¯t) is presented. The analysis uses proton-proton collision data at √s = 13TeV, recorded by the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 140 fb−1. Events with two same-charge leptons and at least two b-tagged jets are selected. Neural networks are employed to define two selections sensitive to additional couplings beyond the Standard Model that would enhance the production rate of same-sign top-quark pairs. No significant signal is observed, leading to an upper limit on the total production cross-section of same-sign top-quark pairs of 1.6 fb at 95% confidence level. Corresponding limits on the three Wilson coefficients associated with the O(1)tu, O(1)Qu, and O(8)Qu operators in the Standard Model Effective Field Theory framework are derived.enOpen Access, Copyright CERN, for the benefit of the ATLAS Collaboration. Article funded by SCOAP3. Open Access. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.Hadron-Hadron ScatteringJournal article10.1007/jhep02(2025)084730464Fewell, M.P. [0000-0002-4406-0430]Jackson, P. [0000-0002-0847-402X]Potti, H. [0000-0002-0800-9902]Ting, E.X.L. [0000-0002-5886-6339]White, M.J. [0000-0001-5474-4580]