Study of jet multiplicity for an Axion-Like Particle search in Light-by-Light scattering with the ATLAS central detector and the ATLAS Forward Proton detector – Summer Student Report

An analysis of jet multiplicity for an ALP search in light-by-light scattering in 13 TeV proton-proton collisions with the ATLAS detector and AFP detector has been performed using the data recorded in 2017 and the simulated data of an ALP mass with 1000 GeV. In order to increase the detection sensitivities, the number of jets was investigated together with the proton matching of the ATLAS central detector and the AFP detector. First, overlap removal was applied on jets to remove double-counted objects, which are also reconstructed as photons in both signal simulation and recorded data. The matching efficiency of the data combined with jet information was calculated for three types of matching criteria, 10% matching, $1\sigma$ matching, and $2\sigma$ matching. The results obtained from the number of matches in signal simulation was found to be consistent with that of the previous analysis. The number of jets was determined for the three matching criteria and compared to that of no matching condition. The resulting distributions of the numbers of jets are quite similar in signal simulation and recorded data, and thus would not contribute much to increasing the sensitivity for detecting an ALP signal.