Status of the PrimEx eta Radiative Decay Width Experiment in Hall D at Jefferson Lab

The PrimEx eta experiment (E12-10-011) at Jefferson Lab performed the first run of a new experiment in Hall D to measure the η radiative decay width with high precision using the GlueX experimental setup. In this experiment the $\eta\rightarrow\gamma\gamma$ decay width will be extracted from the photoproduction of η mesons at extreme forward angles using the so-called Primakoff effect. The two-photon decay of the \eta meson is predominantly due to Chiral anomaly in QCD. The projected 3.2% accuracy of the $\eta\rightarrow\gamma\gamma$ decay width measurement will significantly impact the η-sector of the Particle Data Group’s (PDG) compilation, sizably improving the average value on $\Gamma(\eta\rightarrow\gamma\gamma)$. That, in turn, will improve determination of the rest of the η partial decay widths. It will also significantly improve the $\eta-\eta\prime$ mixing angle. The first run of this experiment was in spring of 2019 to test the capability of the experimental setup. A rich and good statistics initial experimental data set was collected during this run. We are currently analyzing the data to check the experimental method and to prepare for the second full statistics run. The first preliminary physics distributions will be presented and discussed in this talk.