Observation of t(t)over-barγγ production at √s=13 TeV with the ATLAS detector



Aad, G, Aakvaag, E, Abbott, B, Abdelhameed, S, Abeling, K, Abicht, NJ, Abidi, SH, Aboelela, M, Aboulhorma, A, Abramowicz, H
et al (show 2874 more authors) (2026) Observation of t(t)over-barγγ production at √s=13 TeV with the ATLAS detector PHYSICS LETTERS B, 874. p. 140195. ISSN 0370-2693, 1873-2445

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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¯γγ production 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<inf>−0.53</inf>+0.58fb, corresponding to an observed significance of 5.2 standard deviations. Additionally, the ratio of the production cross section of tt¯γγ to top-quark pair production in association with one photon is determined, yielding (3.30<inf>−0.65</inf>+0.70)×10−3.

Item Type: Article
Uncontrolled Keywords: Top-quark pair production in association with two photons
Divisions: Faculty of Science & Engineering
Faculty of Science & Engineering > School of Physical Sciences
Faculty of Science & Engineering > School of Physical Sciences > Physics
Depositing User: Symplectic Admin
Date Deposited: 03 Mar 2026 08:56
Last Modified: 23 May 2026 10:57
DOI: 10.1016/j.physletb.2026.140195
Open Access URL: https://www.sciencedirect.com/science/article/pii/...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3197310
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