The radiative decay width measurement of the η-meson at GlueX

The PrimEx-eta experiment at Jefferson Lab is aiming to measure the radiative decay width of the η-meson via the Primakoff effect. It will provide a critical input to determine the η-η′ mixing angle and the light quark mass ratio model-independently. Three runs were performed with the GlueX experimental setup in Hall D in 2019, 2021, and 2022. We will discuss the status of experiment and how the radiative decay width is extracted from the η-meson photoproduction off a helium nucleus. We will also discuss the measurement of Compton scattering off an atomic electron, which is used to control experimental systematics, including the detection efficiency, the luminosity, and the measurement stability overtime.