This paper presents the first observation of top-quark pair production in association with two photons (𝑡𝑡 ̄ 𝛾𝛾). The measurement is performed in the single-lepton decay channel using proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider. The data correspond to an integrated luminosity of 140 fb−1 recorded during Run 2 at a centre-of-mass energy of 13 TeV. The 𝑡𝑡 ̄ 𝛾𝛾production cross section, measured in a fiducial phase space based on particle-level kinematic criteria for the lepton, photons, and jets, is found to be 2.42+0.58 −0.53 fb, corresponding to an observed significance of 5.2 standard deviations. Additionally, the ratio of the production cross section of 𝑡𝑡 ̄ 𝛾𝛾to top-quark pair production in association with one photon is determined, yielding (3.30+0.70 −0.65) × 10−3.

Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., et al. (2026). Observation of tt¯γγ production at √𝑠 = 13 TeV with the ATLAS detector. PHYSICS LETTERS. SECTION B, 874, 1-19 [10.1016/j.physletb.2026.140195].

Observation of tt¯γγ production at √𝑠 = 13 TeV with the ATLAS detector

Alberghi, G. L.;Alfonsi, F.;Ballabene, E.;Bellagamba, L.;Bianco, G.;Boscherini, D.;Bruni, A.;Carratta, G.;Corchia, F. A.;Cremonini, D.;De Castro, S.;Fabbri, F.;Fabbri, L.;Franchini, M.;Gabrielli, A.;Giacobbe, B.;Lasagni Manghi, F.;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

This paper presents the first observation of top-quark pair production in association with two photons (𝑡𝑡 ̄ 𝛾𝛾). The measurement is performed in the single-lepton decay channel using proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider. The data correspond to an integrated luminosity of 140 fb−1 recorded during Run 2 at a centre-of-mass energy of 13 TeV. The 𝑡𝑡 ̄ 𝛾𝛾production cross section, measured in a fiducial phase space based on particle-level kinematic criteria for the lepton, photons, and jets, is found to be 2.42+0.58 −0.53 fb, corresponding to an observed significance of 5.2 standard deviations. Additionally, the ratio of the production cross section of 𝑡𝑡 ̄ 𝛾𝛾to top-quark pair production in association with one photon is determined, yielding (3.30+0.70 −0.65) × 10−3.
2026
Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., et al. (2026). Observation of tt¯γγ production at √�� = 13 TeV with the ATLAS detector. PHYSICS LETTERS. SECTION B, 874, 1-19 [10.1016/j.physletb.2026.140195].
Aad, G.; Aakvaag, E.; Abbott, B.; Abdelhameed, S.; Abeling, K.; Abicht, N. J.; Abidi, S. H.; Aboelela, M.; Aboulhorma, A.; Abramowicz, H.; Abulaiti, Y...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1049303
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