Speaker
Description
The PrimEx-eta experiment at Jefferson Lab is conducting a new measurement of the radiative decay width of the $\eta$-meson via the Primakoff effect from the $\eta$-meson photoproduction off a helium
nucleus. The produced $\eta$-meson can be reconstructed by detecting either $\eta \to 2\gamma$ or $\eta \to 3\pi$ decays. A precise measurement of $\Gamma(\eta \to \gamma\gamma)$ will improve the
calculation of all $\eta$-meson partial decay widths, particularly enhancing the understanding of the hadronic contribution to the muon magnetic moment from lattice QCD. Furthermore, it will provide
critical input to determine the $\eta$-$\eta'$ mixing angle and the light quark mass ratio in a model-independent manner. The status of the data analysis and its challenges will be presented in this
talk.
| session | K. Precision and New Physics |
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