Data-driven Background Estimate For the H->Za->llγγ Analysis At the ATLAS Experiment

The Higgs boson presents a possible way to observe axion-like particles at the LHC via the H->Za production mode. Axions are hypothetical particles that present potential insights into new physics beyond the standard model, including solutions to the strong CP problem and dark matter. The ATLAS experiment has an extensive BSM particle search program, including searches for axions. This analysis searches for H->Za in the llγγ decay mode due to its clean signature and relatively high branching ratio. The background levels of this decay mode are estimated using a data-driven approach, where data events outside of the signal region are analyzed to estimate background levels inside of the signal region. This talk presents the data-driven background estimate and the evaluation of the spurious signal uncertainty on the estimate.