Measurement of the Electromagnetic Transition Form Factor of the ${\eta }^{\prime }$ Meson

Electromagnetic Transition Form Factors (TFF) allow us to study the intrinsic structures of hadrons and gain knowledge of their compound particles and properties. Furthermore the TFF of the light pseudoscalar mesons are an important quantity to reduce the theoretical uncertainty of the hadronic light-by-light scattering of the anomalous magnetic moment of the muon. These TFF are accessible in accelerator experiments like the Mainzer Mikrotron (MAMI) and the Crystal Ball experiment via particle decays in the time-like region. In the A2 collaboration at MAMI experiments with bremsstrahlung photons are conducted. In 2014 dedicated experiments for the photoproduction of ${\eta }^{\prime }$ and $\omega$ mesons took place with a special photon tagging device constructed mainly for measurements of the ${\eta }^{\prime }$, the so-called End-point Tagger, covering the high-energetic region of the bremsstrahlung spectrum. In this contribution the measurement of the Dalitz decay ${\eta }^{\prime }$$\to$$\gamma$*$\gamma$$\to$$e^{+}{e}^{-}\gamma$ with the Crystal Ball and TAPS setup will be discussed. Simulation studies for the photoproduction processes as well as first results of the 2014 measured data will be presented.