A search is presented for the electroweak production of a top-quark pair in association with a 𝑊 boson and at least one additional jet known as the 𝑡⁢¯𝑡⁢𝑊⁢𝑗EW process. This process has embedded within it a 𝑡⁢𝑊-scattering vertex, which is probed directly for the first time. The collision data were collected with the ATLAS detector during Run 2 of the LHC and correspond to an integrated luminosity of 140  fb−1 at √𝑠 =13  TeV. The search uses same-charge pairs of electrons and muons together with jets, of which at least one is 𝑏-tagged. The properties of the most forward jet relative to the rest of the event are used to discriminate the electroweak 𝑡⁢¯𝑡⁢𝑊⁢𝑗EW production process from its strong 𝑡⁢¯𝑡⁢𝑊 production counterpart. A measured (expected) 95% CL upper limit on the cross section is set at 𝜎𝑡⁢¯𝑡 ⁢𝑊⁢𝑗EW <251  fb (230 fb), to be compared with the expected Standard Model (SM) cross section of 47.7 fb. Limits are set on the SM effective field theory (EFT) operators 𝑂𝐻⁡𝑡 and 𝑂(1)𝐻⁡𝑄, which modify the electroweak couplings of the top quark through contributions to the 𝑡⁢𝑊-scattering vertex. The interpretation acts as a case study to emphasize the importance of energy-dependent sensitivity, multiprocess, and multioperator EFT contributions.

Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N. j., et al. (2026). Search for electroweak 𝑡⁢¯𝑡⁢𝑊⁢𝑗 production in multileptonic final states at √𝑠 =13  TeV with the ATLAS detector and bounds on effective field theory operators. PHYSICAL REVIEW D, 114(1), 012001-1-01291-34 [10.1103/p5nz-95m3].

Search for electroweak 𝑡⁢¯𝑡⁢𝑊⁢𝑗 production in multileptonic final states at √𝑠 =13  TeV with the ATLAS detector and bounds on effective field theory operators

Alfonsi, F.;Ballabene, E.;Bellagamba, L.;Bianco, G.;Boscherini, D.;Bruni, A.;Carratta, G.;Clissa, L.;Corchia, F.  A.;Cremonini, D.;De Castro, S.;Fabbri, F.;Fabbri, L.;Franchini, M.;Gabrielli, A.;Giacobbe, B.;Lasagni Manghi, F.;Levrini, G.;Nechaeva, S.;Polini, A.;Rinaldi, L.;Romano, M.;Sanzani, E.;Sbarra, C.;Sbrizzi, A.;Semprini-Cesari, N.;Sioli, M.;Todome, K.;Valentinetti, S.;Villa, M.;Vittori, C.;Vivarelli, I.;Zoccoli, A.;
2026

Abstract

A search is presented for the electroweak production of a top-quark pair in association with a 𝑊 boson and at least one additional jet known as the 𝑡⁢¯𝑡⁢𝑊⁢𝑗EW process. This process has embedded within it a 𝑡⁢𝑊-scattering vertex, which is probed directly for the first time. The collision data were collected with the ATLAS detector during Run 2 of the LHC and correspond to an integrated luminosity of 140  fb−1 at √𝑠 =13  TeV. The search uses same-charge pairs of electrons and muons together with jets, of which at least one is 𝑏-tagged. The properties of the most forward jet relative to the rest of the event are used to discriminate the electroweak 𝑡⁢¯𝑡⁢𝑊⁢𝑗EW production process from its strong 𝑡⁢¯𝑡⁢𝑊 production counterpart. A measured (expected) 95% CL upper limit on the cross section is set at 𝜎𝑡⁢¯𝑡 ⁢𝑊⁢𝑗EW <251  fb (230 fb), to be compared with the expected Standard Model (SM) cross section of 47.7 fb. Limits are set on the SM effective field theory (EFT) operators 𝑂𝐻⁡𝑡 and 𝑂(1)𝐻⁡𝑄, which modify the electroweak couplings of the top quark through contributions to the 𝑡⁢𝑊-scattering vertex. The interpretation acts as a case study to emphasize the importance of energy-dependent sensitivity, multiprocess, and multioperator EFT contributions.
2026
Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N. j., et al. (2026). Search for electroweak ��⁢¯��⁢��⁢�� production in multileptonic final states at √�� =13  TeV with the ATLAS detector and bounds on effective field theory operators. PHYSICAL REVIEW D, 114(1), 012001-1-01291-34 [10.1103/p5nz-95m3].
Aad, G.; Aakvaag, E.; Abbott, B.; Abdelhameed, S.; Abeling, K.; Abicht, N.  j.; Abidi, S.  h.; Aboelela, M.; Aboulhorma, A.; Abramowicz, H.; Abulaiti,...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1088555
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