2025 Articles

Search for same-charge top-quark pair production in 𝑝𝑝 collisions at √𝑠 = 13 TeV with the ATLAS detector

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.; Adye, T.; Affolder, A. A.; Afik, Y.; Agaras, M. N.; Aggarwal, A.; Agheorghiesei, C.; Ahmadov, F.; Ahuja, S.; Ai, X.; Aielli, G.; Aikot, A.; Ait Tamlihat, M.; Aitbenchikh, B.; Akbiyik, M.; Åkesson, T. P. A.; Akimov, A. V.; Akiyama, D.; Akolkar, N. N.; Aktas, S.; Al Khoury, Konie; Angerami, Aaron; Busch, Elena Laura; Brooijmans, Gustaaf H.

A search for the production of top-quark pairs with the same electric charge 𝑡𝑡 or 𝑡̄𝑡̄) is presented. The analysis uses proton-proton collision data at √𝑠 = 13 TeV, 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.