Status of the PrimEx-Eta Experiment in Hall D at Jefferson Lab*

The η→γγ decay proceeds primarily through the chiral anomaly. A precise measurement of this decay width will provide critical input to extract the η-η' mixing angle and the light quark mass ratio, while also improving the precision on all other η-meson partial decay widths. Previous measurements of this decay width through e⁺e^- collider experiments differ from the result of the sole Primakoff experiment by more than 4σ. To address this discrepancy and to reduce the total uncertainty for the decay width, the PrimEx-Eta fixed-target experiment in Hall D at Jefferson Lab (E12-10-011\footnote{Spokespersons: A. Gasparian (contact), L. Gan, I. Larin, A. Somov}) will perform a precision measurement of the η→γγ decay width using the Primakoff method. The first two runs of the experiment were completed in Spring 2019 and Fall 2021, with the third and final run scheduled to finish this Fall. In this talk we will discuss the status of the experiment and the steps toward extracting the radiative decay width. Simultaneous with the η decay width measurement, the total cross section for Compton scattering off the atomic electrons is being measured. This well-understood QED process is used to verify the overall systematic uncertainties associated with a cross section measurment in the forward direction. In this talk we will also present preliminary results for the integrated total Compton scattering cross section.