Cross-sections for the production of a Z boson in association with two photons are measured in proton–proton collisions at a centre-of-mass energy of 13 TeV. The data used correspond to an integrated luminosity of 139 fb−1 recorded by the ATLAS experiment during Run 2 of the LHC. The measurements use the electron and muon decay channels of the Z boson, and a fiducial phase-space region where the photons are not radiated from the leptons. The integrated Z(→ )γ γ cross-section is measured with a precision of 12% and differential cross-sections are measured as a function of six kinematic variables of the Zγ γ system. The data are compared with predictions from MC event generators which are accurate to up to next-to-leading order in QCD. The cross-section measurements are used to set limits on the coupling strengths of dimension-8 operators in the framework of an effective field theory.

Aad, G., Abbott, B., Abbott, D.C., Abud, A.A., Abeling, K., Abhayasinghe, D.K., et al. (2023). Measurement of Z γ γ production in pp collisions at √s=13 TeV with the ATLAS detector. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 83(6), 539-1-539-30 [10.1140/epjc/s10052-023-11579-8].

Measurement of Z γ γ production in pp collisions at √s=13 TeV with the ATLAS detector

Alberghi, GL;Alfonsi, F;Bindi, M;Boscherini, D;Cabras, G;De Castro, S;Fabbri, F;Fabbri, L;Franchini, M;Gabrielli, A;Massa, L;Monzani, S;Polini, A;