Measuring Electron-Photon Misidentification in the ATLAS Detector Using Z$\rightarrow e^+e^-$ Decay

The rate at which electrons are misidentified as photons in the ATLAS detector is an essential parameter in many physics analyses. This study proposes a method to measure this rate in early data using Z boson decay. The data-driven method involves examination of Z events identified as decaying in one of three ways: to an electron- positron pair, to an electron or positron plus one photon, or to two photons. Through isolating the number of events in the e$\gamma$ and $\gamma\gamma$ final states that come from misidentified electrons, an overall electron-photon misidentification rate can be extracted.