Searching for axion-like particles with data scouting at ATLAS and CMS

We investigate the physics case for a dedicated trigger-level analysis for very low mass diphoton resonances at ATLAS and CMS and introduce a new photon isolation criterion. This greatly increases the acceptance for light particles at the expense of a somewhat larger Standard Model background. We show how such an analysis would likely yield new experimental coverage for axion-like particles for masses below 15 GeV, bridging the gap with the region covered by flavor factories.