PT Journal AU ATLAS Collaboration (Aad, Gea Alvarez Piqueras, D Aparisi Pozo, JA Bailey, AJ Cabrera Urban, S Castillo, FL Castillo Gimenez, V Cerda Alberich, L Costa, MJ Escobar, C Estrada Pastor, O Ferrer, A Fiorini, L Fullana Torregrosa, E Fuster, J Garcia, C Garcia Navarro, JE Gonzalez de la Hoz, S Gonzalvo Rodriguez, GR Guerrero Rojas, JG Higon-Rodriguez, E Lacasta, C Lozano Bahilo, JJ Madaffari, D Mamuzic, J Marti-Garcia, S Melini, D MiƱano, M Mitsou, VA Rodriguez Bosca, S Rodriguez Rodriguez, D Ruiz-Martinez, A Salt, J Santra, A Soldevila, U Sanchez, J Valero, A Valls Ferrer, JA Vos, M TI Measurement of the Z(-> l(+)l(-))gamma production cross-section in pp collisions at root s=13 TeV with the ATLAS detector SO Journal of High Energy Physics JI J. High Energy Phys. PY 2020 BP 054 EP 52pp VL 03 IS 3 DI 10.1007/JHEP03(2020)054 LA English DE Hadron-Hadron scattering (experiments) AB The production of a prompt photon in association with a Z boson is studied in proton-proton collisions at a centre-of-mass energy s = 13 TeV. The analysis uses a data sample with an integrated luminosity of 139 fb(-1) collected by the ATLAS detector at the LHC from 2015 to 2018. The production cross-section for the process pp -> l(+)l(-)gamma + X (l = e, mu) is measured within a fiducial phase-space region defined by kinematic requirements on the photon and the leptons, and by isolation requirements on the photon. An experimental precision of 2.9% is achieved for the fiducial cross-section. Differential cross-sections are measured as a function of each of six kinematic variables characterising the l(+)l(-)gamma system. The data are compared with theoretical predictions based on next-to-leading-order and next-to-next-to-leading-order perturbative QCD calculations. The impact of next-to-leading-order electroweak corrections is also considered. ER