Optimization of diphoton acoplanarity for an Axion-Like Particle in Light-by-Light scattering with the ATLAS detector at CERN

In 2017, 32 fb−1 of pp collisions data at √s = 13 TeV were recorded with the ATLAS central detectorandtheATLASForwardProton(AFP)detectorsattheLargeHadronCollider. Ananalysis for Axion-Like Particles (ALPs) mediated by light-by-light scattering is being performed using a simulated ALP signal and the data from 2017. In this initial analysis, a simulation with ALP mass 1000 GeV and coupling constant g = 0.001 GeV−1 was performed and ALPs with masses in range between 200 GeV and 2000 GeV have also been studied on the generator level. The diphoton acoplanarity distribution differs according to their ALPs masses. In this study, using signal files with detector simulation and on generated level, the optimum acoplanarity selection cut for ALP masses in the range 200 GeV and 2000 GeV are estimated by calculating the significance.