Aad, G.Abbott, B.Abeling, K.Abicht, N.J.Abidi, S.H.Aboulhorma, A.Abramowicz, H.Abreu, H.Abulaiti, Y.Abusleme Hoffman, A.C.Acharya, B.S.Adam Bourdarios, C.Adamczyk, L.Adamek, L.Addepalli, S.V.Addison, M.J.Adelman, J.Adiguzel, A.Adye, T.Affolder, A.A.et al.2023-12-192023-12-192023Journal of High Energy Physics (JHEP), 2023; 2023(7):1-371029-84791029-8479https://hdl.handle.net/2440/140233A search for forward proton scattering in association with light-by-light scattering mediated by an axion-like particle is presented, using the ATLAS Forward Proton spectrometer to detect scattered protons and the central ATLAS detector to detect pairs of outgoing photons. Proton-proton collision data recorded in 2017 at a centre-of-mass energy of √s = 13 TeV were analysed, corresponding to an integrated luminosity of 14.6 fb−1. A total of 441 candidate events were selected. A search was made for a narrow resonance in the diphoton mass distribution, corresponding to an axion-like particle (ALP) with mass in the range 150–1600 GeV. No excess is observed above a smooth background. Upper limits on the production cross section of a narrow resonance are set as a function of the mass, and are interpreted as upper limits on the ALP production coupling constant, assuming 100% decay branching ratio into a photon pair. The inferred upper limit on the coupling constant is in the range 0.04–0.09 TeV−1 at 95% confidence level.en© CERN, for the benefit of the ATLAS Collaboration. Article funded by SCOAP3 . This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.CP Violation; Hadron-Hadron ScatteringJournal article10.1007/jhep07(2023)2342023-12-19642115Filmer, E.K. [0000-0001-6967-7325]Jackson, P. [0000-0002-0847-402X]McDougall, A.E. [0000-0001-7713-2800]Potti, H. [0000-0002-0800-9902]Ting, E.X.L. [0000-0002-5886-6339]White, M.J. [0000-0001-5474-4580]