A 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 root s = 13TeV 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 0.04-0.09TeV-1 at 95% confidence level.

Aad, G., Abbott, B., Abeling, K., Abicht, N.J., Abidi, S.H., Aboulhorma, A., et al. (2023). Search for an axion-like particle with forward proton scattering in association with photon pairs at ATLAS. JOURNAL OF HIGH ENERGY PHYSICS, 2023(7) [10.1007/jhep07(2023)234].

Search for an axion-like particle with forward proton scattering in association with photon pairs at ATLAS

B. Di Micco;R. Di Nardo;A. D'Onofrio;D. Orestano;